UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13G Under the Securities Exchange Act of 1934 Align Technologies, Inc. - -------------------------------------------------------------------------------- (Name of Issuer) Common Stock, par value $.0001 per share - -------------------------------------------------------------------------------- (Title of Class of Securities) 016255101 ------------------------------- (CUSIP Number) December 31, 2001 - -------------------------------------------------------------------------------- (Date of Event Which Requires Filing of this Statement) Check the appropriate box to designate the rule pursuant to which this Schedule is filed: [_] Rule 13d-1(b) [_] Rule 13d-1(c) [X] Rule 13d-1(d) Page 1 of 6 pages

Cusip No. 016255101 13G Page 1 of 6 - -------------------------------------------------------------------------------- 1. Name of Reporting Persons: Carlyle Partners III, L.P. I.R.S. Identification Nos. of above persons (entities only): 52-2229944 - -------------------------------------------------------------------------------- 2. Check the Appropriate Box if a Member of a Group (See Instructions) - -------------------------------------------------------------------------------- (a) [_] - -------------------------------------------------------------------------------- (b) [x] - -------------------------------------------------------------------------------- 3. SEC Use Only - -------------------------------------------------------------------------------- 4. Citizenship or Place of Organization: Delaware - -------------------------------------------------------------------------------- Number of Shares 5. Sole Voting Power -0- Beneficially Owned By Each Reporting Person ----------------------------------------------------- With 6. Shared Voting Power 2,895,096 ----------------------------------------------------- 7. Sole Dispositive Power -0- ----------------------------------------------------- 8. Shared Dispositive Power 2,895,096 - -------------------------------------------------------------------------------- 9. Aggregate Amount Beneficially Owned by Each Reporting Person: 2,895,096 - -------------------------------------------------------------------------------- 10. Check if the Aggregate Amount in Row (11) Excludes Certain Shares (See Instructions): [_] N/A - -------------------------------------------------------------------------------- 11. Percent of Class Represented by Amount in Row (11): 6.0% - -------------------------------------------------------------------------------- 12. Type of Reporting Person (See Instructions): PN - -------------------------------------------------------------------------------- - -------------------------------------------------------------------------------- - -------------------------------------------------------------------------------- - -------------------------------------------------------------------------------- - -------------------------------------------------------------------------------- - -------------------------------------------------------------------------------- - -------------------------------------------------------------------------------- Page 2 of 16 pages

Cusip No. 016255101 13G Page 2 of 6 - -------------------------------------------------------------------------------- 1. Name of Reporting Persons: CP III Coinvestment, L.P. I.R.S. Identification Nos. of above persons (entities only): 54-1970037 - -------------------------------------------------------------------------------- 2. Check the Appropriate Box if a Member of a Group (See Instructions) - -------------------------------------------------------------------------------- (a) [_] - -------------------------------------------------------------------------------- (b) [X] - -------------------------------------------------------------------------------- 3. SEC Use Only - -------------------------------------------------------------------------------- 4. Citizenship or Place of Organization: Delaware - -------------------------- ----------------------------------------------------- Number of Shares 5. Sole Voting Power -0- Beneficially Owned By Each Reporting Person With ----------------------------------------------------- 6. Shared Voting Power 74,616 ----------------------------------------------------- 7. Sole Dispositive Power -0- ----------------------------------------------------- 8. Shared Dispositive Power 74,616 ----------------------------------------------------- 9. Aggregate Amount Beneficially Owned by Each Reporting Person: 74,616 - -------------------------------------------------------------------------------- 10. Check if the Aggregate Amount in Row (11) Excludes Certain Shares (See Instructions): [_] N/A - -------------------------------------------------------------------------------- 11. Percent of Class Represented by Amount in Row (11): 0.1% - -------------------------------------------------------------------------------- 12. Type of Reporting Person (See Instructions): PN - -------------------------------------------------------------------------------- - -------------------------------------------------------------------------------- - -------------------------------------------------------------------------------- - -------------------------------------------------------------------------------- - -------------------------------------------------------------------------------- - -------------------------------------------------------------------------------- - -------------------------------------------------------------------------------- Page 3 of 16 pages

Cusip No. 016255101 13G Page 3 of 6 - -------------------------------------------------------------------------------- 1. Name of Reporting Persons: TC Group III, L.P. I.R.S. Identification Nos. of above persons (entities only): 52-2287893 - -------------------------------------------------------------------------------- 2. Check the Appropriate Box if a Member of a Group (See Instructions) - -------------------------------------------------------------------------------- (a) [_] - -------------------------------------------------------------------------------- (b) [X] - -------------------------------------------------------------------------------- 3. SEC Use Only - -------------------------------------------------------------------------------- 4. Citizenship or Place of Organization: Delaware - -------------------------- ----------------------------------------------------- Number of Shares 5. Sole Voting Power -0- Beneficially Owned By Each Reporting Person With ----------------------------------------------------- 6. Shared Voting Power 2,969,712 ----------------------------------------------------- 7. Sole Dispositive Power -0- ----------------------------------------------------- 8. Shared Dispositive Power 2,969,712 ----------------------------------------------------- 9. Aggregate Amount Beneficially Owned by Each Reporting Person: 2,969,712 - -------------------------------------------------------------------------------- 10. Check if the Aggregate Amount in Row (11) Excludes Certain Shares (See Instructions): [_] N/A - -------------------------------------------------------------------------------- 11. Percent of Class Represented by Amount in Row (11): 6.1% - -------------------------------------------------------------------------------- 12. Type of Reporting Person (See Instructions): PN - -------------------------------------------------------------------------------- - -------------------------------------------------------------------------------- - -------------------------------------------------------------------------------- - -------------------------------------------------------------------------------- - -------------------------------------------------------------------------------- - -------------------------------------------------------------------------------- - -------------------------------------------------------------------------------- Page 4 of 16 pages

Cusip No. 016255101 13G Page 4 of 6 - -------------------------------------------------------------------------------- 1. Name of Reporting Persons: TC Group III, L.L.C. I.R.S. Identification Nos. of above persons (entities only): N/A - -------------------------------------------------------------------------------- 2. Check the Appropriate Box if a Member of a Group (See Instructions) - -------------------------------------------------------------------------------- (a) [_] - -------------------------------------------------------------------------------- (b) [x] - -------------------------------------------------------------------------------- 3. SEC Use Only - -------------------------------------------------------------------------------- 4. Citizenship or Place of Organization: Delaware - -------------------------------------------------------------------------------- Number of Shares 5. Sole Voting Power -0- ----------------------------------------------------- Beneficially Owned By 6. Shared Voting Power 2,969,712 ----------------------------------------------------- Each Reporting Person 7. Sole Dispositive Power -0- ----------------------------------------------------- With 8. Shared Dispositive Power 2,969,712 - -------------------------------------------------------------------------------- 9. Aggregate Amount Beneficially Owned by Each Reporting Person: 2,969,712 - -------------------------------------------------------------------------------- 10. Check if the Aggregate Amount in Row (11) Excludes Certain Shares (See Instructions): [_] N/A - -------------------------------------------------------------------------------- 11. Percent of Class Represented by Amount in Row (11): 6.1% - -------------------------------------------------------------------------------- 12. Type of Reporting Person (See Instructions): OO (Limited Liability Company) - -------------------------------------------------------------------------------- - -------------------------------------------------------------------------------- - -------------------------------------------------------------------------------- - -------------------------------------------------------------------------------- - -------------------------------------------------------------------------------- - -------------------------------------------------------------------------------- - -------------------------------------------------------------------------------- Page 5 of 16 pages

Cusip No. 016255101 13G Page 5 of 6 - -------------------------------------------------------------------------------- 1. Name of Reporting Persons: TC Group, L.L.C. I.R.S. Identification Nos. of above persons (entities only): 54-1686957 - -------------------------------------------------------------------------------- 2. Check the Appropriate Box if a Member of a Group (See Instructions) - -------------------------------------------------------------------------------- (a) [_] - -------------------------------------------------------------------------------- (b) [x] - -------------------------------------------------------------------------------- 3. SEC Use Only - -------------------------------------------------------------------------------- 4. Citizenship or Place of Organization: Delaware - -------------------------------------------------------------------------------- Number of Shares 5. Sole Voting Power -0- ----------------------------------------------------- Beneficially Owned By 6. Shared Voting Power 2,969,712 ----------------------------------------------------- Each Reporting Person 7. Sole Dispositive Power -0- ----------------------------------------------------- With 8. Shared Dispositive Power 2,969,712 - -------------------------------------------------------------------------------- 9. Aggregate Amount Beneficially Owned by Each Reporting Person: 2,969,712 - -------------------------------------------------------------------------------- 10. Check if the Aggregate Amount in Row (11) Excludes Certain Shares (See Instructions): [_] N/A - -------------------------------------------------------------------------------- 11. Percent of Class Represented by Amount in Row (11): 6.1% - -------------------------------------------------------------------------------- 12. Type of Reporting Person (See Instructions): OO (Limited Liability Company) - -------------------------------------------------------------------------------- - -------------------------------------------------------------------------------- - -------------------------------------------------------------------------------- - -------------------------------------------------------------------------------- - -------------------------------------------------------------------------------- - -------------------------------------------------------------------------------- - -------------------------------------------------------------------------------- Page 6 of 16 pages

Cusip No. 016255101 13G Page 6 of 6 - -------------------------------------------------------------------------------- 1. Name of Reporting Persons: TCG Holdings, L.L.C. I.R.S. Identification Nos. of above persons (entities only): 54-1686011 - -------------------------------------------------------------------------------- 2. Check the Appropriate Box if a Member of a Group (See Instructions) - -------------------------------------------------------------------------------- (a) [_] - -------------------------------------------------------------------------------- (b) [X] - -------------------------------------------------------------------------------- 3. SEC Use Only - -------------------------------------------------------------------------------- 4. Citizenship or Place of Organization: Delaware - -------------------------------------------------------------------------------- Number of Shares 5. Sole Voting Power -0- Beneficially Owned By ------------------------------------------------------- Each Reporting Person 6. Shared Voting Power 2,969,712 With ------------------------------------------------------- 7. Sole Dispositive Power -0- ------------------------------------------------------- 8. Shared Dispositive Power 2,969,712 - -------------------------------------------------------------------------------- 9. Aggregate Amount Beneficially Owned by Each Reporting Person: 2,969,712 - -------------------------------------------------------------------------------- 10. Check if the Aggregate Amount in Row (11) Excludes Certain Shares (See Instructions): [_] N/A - -------------------------------------------------------------------------------- 11. Percent of Class Represented by Amount in Row (11): 6.1% - -------------------------------------------------------------------------------- 12. Type of Reporting Person (See Instructions): OO (Limited Liability Company) - -------------------------------------------------------------------------------- - -------------------------------------------------------------------------------- - -------------------------------------------------------------------------------- - -------------------------------------------------------------------------------- - -------------------------------------------------------------------------------- - -------------------------------------------------------------------------------- - -------------------------------------------------------------------------------- Page 7 of 16 pages

Item 1. (a) Name of Issuer: Align Technologies, Inc (b) Address of Issuer's Principal Executive Offices: 851 Martin Avenue, Santa Clara, California 95050. Item 2. (a) Name of Person Filing: Carlyle Partners III, L.P., a Delaware limited partnership CP III Coinvestment, L.P., a Delaware limited partnership TC Group III, L.P., a Delaware limited partnership TC Group III, L.L.C., a Delaware limited liability company TC Group, L.L.C., a Delaware limited liability company TCG Holdings, L.L.C., a Delaware limited liability company. (b) Address of Principal Business Office or, if none, Residence: c/o The Carlyle Group 1001 Pennsylvania Avenue, N.W., Suite 220 South, Washington, D.C. 20004-2505. (c) Citizenship: Carlyle Partners III, L.P., a Delaware limited partnership CP III Coinvestment, L.P., a Delaware limited partnership TC Group III, L.P., a Delaware limited partnership TC Group III, L.L.C., a Delaware limited liability company TC Group, L.L.C., a Delaware limited liability company TCG Holdings, L.L.C., a Delaware limited liability company. (d) Title of Class of Securities: Common Stock, par value $.0001 per share Page 8 of 16 pages

(e) CUSIP Number: 016255101 Item 3. If this statement is filed pursuant to ss.ss. 240.13d-1(b) or 240.13d-2(b) or (c), check whether the person filing is a: Not Applicable. Item 4. Ownership Sole power to Shared power Amount Percent Sole power to Shared power dispose or to to dispose or to beneficially of class: vote or direct to vote or to direct the direct the Reporting Person: owned: the vote: direct the vote: disposition of: disposition of: ------------------------------------------------------------------------------------------------- TCG Holdings, L.L.C. 2,969,712 6.1% 0 2,969,712 0 2,969,712 - --------------------------------------------------------------------------------------------------------------------------- TC Group, L.L.C. 2,969,712 6.1% 0 2,969,712 0 2,969,712 - --------------------------------------------------------------------------------------------------------------------------- TC Group III, L.L.C. 2,969,712 6.1% 0 2,969,712 0 2,969,712 - --------------------------------------------------------------------------------------------------------------------------- TC Group III, L.P. 2,969,712 6.1% 0 2,969,712 0 2,969,712 - --------------------------------------------------------------------------------------------------------------------------- Carlyle Partners III, L.P. 2,895,096 6.0% 0 2,895,096 0 2,895,096 - --------------------------------------------------------------------------------------------------------------------------- CP III Coinvestment, L.P. 74,616 .1% 0 74,616 0 74,616 - --------------------------------------------------------------------------------------------------------------------------- Each of the entities listed below is the record owners of the number of shares of Common Stock, par value $0.0001 per share, of Align Technologies, Inc. (the "Common Stock") set forth opposite such entities name below: Record Holders Shares Held of Record - -------------- --------------------- Carlyle Partners III, L.P. 2,895,096 CP III Coinvestment, L.P. 74,616 TC Group III, L.P. is the sole general partner of Carlyle Partners III, L.P. and CP III Coinvestment, L.P. TC Group III, L.L.C. is the sole general partner of TC Group III, L.P. TC Group, L.L.C. is the sole managing member of TC Group III, L.L.C. TCG Holdings, L.L.C. is the sole managing member of TC Group, L.L.C. Accordingly, (i) TC Group III, L.P. and TC Group III, L.L.C. each may be deemed to be a beneficial owner of shares of Common Stock owned of record by each of Carlyle Partners III, L.P. and CP III Coinvestment, L.P.; and (ii) TC Group, L.L.C. and TCG Holdings, L.L.C. each may be deemed to be a beneficial owner of the shares of Common Stock owned of record by Carlyle Partners III, L.P. and CP III Coinvestment, L.P. William E. Conway, Jr., Daniel A D'Aniello and David M. Rubenstein are managing members (the "TCG Holdings Managing Members") of TCG Holdings, L.L.C. and, in such capacity, may be deemed to share beneficial ownership of shares of Common Stock beneficially owned by TCG Holdings, L.L.C. Such individuals expressly disclaim any such beneficial ownership. Each of the TCG Holdings Managing Members is a citizen and resident of the United States. Page 9 of 16 pages

Item 5. Ownership of Five Percent or Less of a Class Not Applicable. Item 6. Ownership of More than Five Percent on Behalf of Another Person. Not Applicable. Item 7. Identification and Classification of the Subsidiary Which Acquired the Security Being Reported on By the Parent Holding Company Not Applicable. Item 8 Identification and Classification of Members of the Group Not Applicable. Item 9. Notice of Dissolution of Group Not Applicable. Item 10. Certification Not Applicable. Page 10 of 16 pages

SIGNATURE After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct. Dated: February 13, 2002 CARLYLE PARTNERS III, L.P. By: TC Group III, L.P., its General Partner By: TC Group III, L.L.C., its General Partner By: TC Group, L.L.C., its Managing Member By: TCG Holdings, L.L.C., its Managing Member By: /s/ Willam E. Conway, Jr. ------------------------------------------- Name: Willam E. Conway, Jr. Title: Managing Director CP III COINVESTMENT, L.P. By: TC Group III, L.P., its General Partner By: TC Group III, L.L.C., its General Partner By: TC Group, L.L.C., its Managing Member By: TCG Holdings, L.L.C., its Managing Member By: /s/ Willam E. Conway, Jr. --------------------------------------- Name: Willam E. Conway, Jr. Title: Managing Director TC GROUP III, L.P. By: TC Group III, L.L.C., its General Partner By: TC Group, L.L.C., its Managing Member By: TCG Holdings, L.L.C., its Managing Member By: /s/ Willam E. Conway, Jr. ------------------------------------------- Name: Willam E. Conway, Jr. Title: Managing Director TC GROUP III, L.L.C. By: TC Group, L.L.C., its Managing Member By: TCG Holdings, L.L.C., its Managing Member By: /s/ Willam E. Conway, Jr. ------------------------------------------- Name: Willam E. Conway, Jr. Title: Managing Director Page 11 of 16 pages

TC GROUP, L.L.C. By: TCG Holdings, L.L.C., its Managing Member By: /s/ Willam E. Conway, Jr. ------------------------------------ Name: Title: Managing Director TCG HOLDINGS, L.L.C. By: /s/ Willam E. Conway, Jr. ------------------------------------ Name: Willam E. Conway, Jr. Title: Managing Director Page 12 of 16 pages

LIST OF EXHIBITS Exhibit No. Description - ----------- ----------- A Joint Filing Agreement Page 13 of 16 pages

EXHIBIT A: Joint Filing Agreement --------------------------------- In accordance with Rule 13d-1(k) promulgated under the Securities Exchange Act of 1934, as amended, the undersigned hereby agree to the joint filing with all other Reporting Persons (as such term is defined in the Schedule 13G referred to below) on behalf of each of them of a statement on Schedule 13G (including amendments thereto) with respect to the common stock, par value $0.0001 per share, of Align Technologies, Inc., a Delaware corporation, and that this Agreement may be included as an Exhibit to such joint filing. This Agreement may be executed in any number of counterparts, all of which taken together shall constitute one and the same instrument. [Remainder of this page has been left intentionally blank.] Page 14 of 16 pages

Signature Page 1 of 2 IN WITNESS WHEREOF, the undersigned hereby execute this Agreement as of the 13th day of February, 2002. CARLYLE PARTNERS III, L.P. By: TC Group III, L.P., its General Partner By: TC Group III, L.L.C., its General Partner By: TC Group, L.L.C., its Managing Member By: TCG Holdings, L.L.C., its Managing Member By: /s/ Willam E. Conway, Jr. -------------------------------------------- Name: Willam E. Conway, Jr. --------------------- Title: Managing Director CP III COINVESTMENT, L.P. By: TC Group III, L.P., its General Partner By: TC Group III, L.L.C., its General Partner By: TC Group, L.L.C., its Managing Member By: TCG Holdings, L.L.C., its Managing Member By: /s/ Willam E. Conway, Jr. -------------------------------------------- Name: Willam E. Conway, Jr. Title: Managing Director TC GROUP III, L.P. By: TC Group III, L.L.C., its General Partner By: TC Group, L.L.C., its Managing Member By: TCG Holdings, L.L.C., its Managing Member By: /s/ Willam E. Conway, Jr. -------------------------------------------- Name: Willam E. Conway, Jr. -------------------------- Title: Managing Director TC GROUP III, L.L.C. By: TC Group, L.L.C., its Managing Member By: TCG Holdings, L.L.C., its Managing Member By: /s/ Willam E. Conway, Jr. -------------------------------------------- Name: Willam E. Conway, Jr. Title: Managing Director TC GROUP, L.L.C. By: TCG Holdings, L.L.C., its Managing Member Page 15 of 16 pages

By: /s/ Willam E. Conway, Jr. ---------------------------------- Name: Willam E. Conway, Jr. Title: Managing Director TCG HOLDINGS, L.L.C. By: /s/ Willam E. Conway, Jr. ---------------------------------- Name: Willam E. Conway, Jr. Title: Managing Director