California Governor Arnold Schwarzenegger has signed a bill creating an annual day of recognition for pioneering gay rights activist Harvey Milk, officials said Monday.

The designation of each May 22 as "Harvey Milk Day" encourages schools around the state to commemorate the murdered gay politician, whose life was the subject of the Oscar-winning 2008 film "Milk."

Milk was California's first openly gay elected official. He was shot to death, along with San Francisco's mayor, by a former city supervisor in 1978. His birthday was May 22.

Schwarzenegger vetoed a similar bill last year, saying Milk's legacy "should continue to be recognized at the local level."

While gay rights groups praised the governor's signing of the bill, conservative groups reacted with scorn.

Deriding it as "Gay Day," the Pacific Justice Institute criticized the bill and said it "offers no opt-out provisions for parents who might not want their children to focus on sexuality for an entire school day."

"It is no wonder schoolchildren in California are struggling on standardized tests, when lawmakers continue to promote political correctness in the classroom over academic achievement," said Brad Dacus, president of the institute.