Exhibit 3.1

AMENDMENT TO AMENDED AND RESTATED BYLAWS

OF ALIGN TECHNOLOGY, INC.

That Article VII, Section 1 of the Company’s Bylaws is amended and restated to read as follows in its entirety:

Section 1. The shares of the Corporation shall be represented by certificates, provided that the Board of Directors may provide by resolution or resolutions that some or all of any or all classes or series of the Corporation’s stock shall be uncertificated shares. Any such resolution shall not apply to shares represented by a certificate until such certificate is surrendered to the Corporation. Every holder of stock of the Corporation represented by certificates shall be entitled to have a certificate signed by, or in the name of the Corporation buy the Chairman or vice-chairperson of the Board of Directors, or the President or vice-president and by the Secretary or an assistant secretary of the Corporation representing the number of shares registered in certificate form. Any or all of the signatures on the certificate may be by a facsimile. In case any officer, transfer agent or registrar who has signed or whose facsimile signature has been placed upon a certificate shall have ceased to be such officer, transfer agent or registrar before such certificate is issued, it may be issued by the Corporation with the same effect as if such person were such officer, transfer agent or registrar at the date of issue. The Corporation shall not have power to issue a certificate in bearer form.

If the Corporation shall be authorized to issue more than one class of stock or more than one series of any class, and such stock is represented by a certificate, the powers, designations, preferences and relative, participating, optional or other special rights of each class of stock or series thereof and the qualification, limitations or restrictions or such preferences and/or rights shall be set forth in full or summarized on the face or back of the certificate which the Corporation shall issues to represent such class or series of stock, provided that, except as otherwise provided in Section 202 of the General Corporation Law of Delaware, in lieu of the foregoing requirements, there may be set forth on the face or back of the certificate which the Corporation issues to represent such class or series of stock, a statement that the Corporation will furnish without charge to each stockholder who so requests the powers, designations, preferences and relative, participating, optional or other special rights of each class of stock or series thereof and the qualifications, limitations or restrictions of such preferences and/or rights. If the stock is not represented by a certificate, then within a reasonable time after the issuance or transfer of uncertificated stock, the corporation shall send to the registered owner thereof a written notice containing the information required to be set forth or stated on certificates pursuant to this Section 1 or a statement that the corporation will furnish without charge to each stockholder who so requests the powers, designations, preferences and relative participating, optional or other special rights of each class of stock or series thereof and the qualifications, limitations or restrictions of such preferences and/or rights.

Article VII, Section 4 of the Company’s Bylaws is amended and restated to read as follows in its entirety:

Section 4. Transfers. Stock of the Corporation shall be transferable in the manner prescribed by law and in these Bylaws. Transfers of stock shall be made on the books of the Corporation only by the record holder of such stock or by his or her attorney lawfully constituted in writing and, if such stock is certificated, upon the surrender of the certificate therefor, which shall be canceled before a new certificate shall be issued.