The San Diego Opera Association (SDO) is a professional opera company located in the city of San Diego, California. It incorporated in 1965, presenting operas under the name of the San Diego Opera. It is a member of the professional association OPERA America, which ranked it among the top ten opera companies in the United States.

The company was founded in 1950 as the San Diego Opera Guild, originally to present traveling productions by San Francisco Opera in the San Diego area. SDO began to stage its own productions in 1965, its first one being La bohème. From the beginning, the company performed at the San Diego Civic Theatre in Downtown San Diego. Until the 2008 recession, it presented five operas each season; in 2008 this was reduced to four productions, scheduled from January to April.

In March 2014 the opera board announced that the 2014 season would be its last, but this decision was later rescinded by the company's board of directors, and a cut down version of the already planned 2015 season was announced, reducing the number of titles from four to three. David Bennett of the Gotham Chamber Opera was hired as general director.