When the San Francisco Symphony canceled an upcoming pair of concerts in North Carolina to protest the state’s law curbing protections for lesbian, gay, bisexual and transgender people, it suddenly found itself with a hole in its calendar. It found a pointed way to fill it.

Michael Tilson Thomas, the orchestra’s music director, is planning “Symphony Pride,” a gala concert to highlight the musical contributions of lesbian and gay composers, with the money it raises going to four nonprofit organizations that provide services for L.G.B.T. people.

Given the contributions gay composers have made to American music, from the avant-garde to Broadway, Mr. Thomas said in an telephone interview that he was surprised to discover that the orchestra had not done a similar concert before. “It just seemed to me to be something that would have happened a number of times,” said Mr. Thomas, who is gay. “But as it turns out, no, as far as we know it hasn’t happened.”

The pride concert, which will be held on April 4 at Davies Symphony Hall in San Francisco, will feature music by composers including Lou Harrison, Henry Cowell, Meredith Monk and John Cage. Audra McDonald will perform a selection of songs by Leonard Bernstein, Stephen Sondheim and Kander and Ebb; she will also narrate Aaron Copland’s “Lincoln Portrait.”