The court ruled the B.C. government had a constitutional right to strip class size and composition provisions from a contract in 2002.
"We fundamentally disagree with the decision which focuses on pre-legislative consultation by government," BCTF president Jim Iker said in a news conference following the ruling.
Four of five appeal court justices agreed the government acted in good faith when it consulted with teachers before making the decision to strip their ability to negotiate limits on class sizes, teacher librarians and special needs student ratios, along with other elements.
The decision has implications outside the classroom, Iker said.
"This decision gives more power to government to undermine collective agreements and workers' rights," he said