Wilson Sonsini Goodrich & Rosati
Professional Corporation 650 Page Mill Road
Palo Alto, California 94304-1050 o: 650.493.9300
f: 650.493.6811

Exhibit 5.1

August 4, 2021

Align Technology, Inc.

410 North Scottsdale Road, Suite 1300

Tempe, Arizona 85281

Re: Registration Statement on Form S-8

Ladies and Gentlemen:

We have examined the Registration Statement on Form S-8 (the “Registration Statement”) to be filed by Align Technology, Inc., a Delaware corporation (“you”), with the Securities and Exchange Commission on or about the date hereof, in connection with the registration under the Securities Act of 1933, as amended, of an aggregate of 2,000,000 shares of your Common Stock, $0.0001 par value (the “Shares”), reserved for issuance pursuant to the Amended and Restated 2010 Employee Stock Purchase Plan (the “ESPP”). As your legal counsel, we have reviewed the actions proposed to be taken by you in connection with the issuance and sale of the Shares under the ESPP.

It is our opinion that the Shares, when issued and sold in the manner described in the ESPP and pursuant to the agreements that accompany the ESPP, will be legally and validly issued, fully paid and nonassessable.

We consent to the use of this opinion as an exhibit to the Registration Statement and further consent to the use of our name wherever appearing in the Registration Statement and any amendments thereto.

Very truly yours,

WILSON SONSINI GOODRICH & ROSATI

Professional Corporation

/s/ WILSON SONSINI GOODRICH & ROSATI

AUSTIN BEIJING BOSTON BRUSSELS HONG KONG LONDON LOS ANGELES NEW YORK PALO ALTO
SAN DIEGO SAN FRANCISCO SEATTLE SHANGHAI WASHINGTON, DC WILMINGTON, DE