The Opposition tabled a private member's bill in April that focused on anti-bullying.
Cam Broten said in Tuesday's question period that the bill would help students to feel safe and respected at school.
"This comes down to the lives of young people in our schools," he said.
Education Minister Don Morgan said school divisions already have to provide gay-straight alliances for students — peer-support groups meant to make gay students feel welcome — when they are requested.
Therefore, he said, legislation isn't necessary.
"It's written policy," Morgan said. "The concern we have is whether there is a school division that isn't doing it."
Morgan added that a resolution was passed unanimously at the latest Saskatchewan Teachers' Federation convention in support of gay-straight alliances.
Broten said the onus shouldn't be on the students to reach out for help.
"This is something where this government needs to set the bar to clearly show that this is the expectation," he said. "This is something that should be enshrined by law."
He added that rates of attempted suicide in schools are one reason why the legislation should be pushed forward.
"This will be raised by a student in the back corner of a classroom to a teacher and not go anywhere," he said. "This is the right thing to do."
In March, Alberta's Progressive Conservative government passed a bill to allow gay-straight alliances in every school if students wanted them.
Faith-based schools had fought gay-straight alliances and the issue divided the house in two previous sessions.