The Assembly had given preliminary approval to the bill on Tuesday but Republicans blocked a final vote until Thursday.
The measure passed 48-43.
It still must clear the Senate and be signed by Gov. Jim Doyle before it becomes law.
Sex education is not required in Wisconsin schools, but for those that chose to provide it would be required to include birth control as part of that instruction under the bill.
The Guttmacher Institute says that 15 states currently require that sex education in schools include instruction on contraception.
