• Wisconsin teacher unions have experienced the largest decline in strength nationwide since 2012, according to a new study.
• The state’s 2011 law, Act 10, is cited as the primary reason for the significant drop in union membership and power.
• Union membership among Wisconsin teachers fell from 98% in 2012 to 45% in 2025, the biggest decrease in the country.

Wisconsin teacher unions have seen the nation’s largest drop in strength since 2012, according to a new study from the Thomas B. Fordham Institute.

The Fordham Institute, a conservative-leaning education think tank, ranked Wisconsin 36th among 50 states and the District of Columbia for teacher union strength, falling 18 spots from its previous 2012 study. The rankings factored in union resources and membership, involvement in politics, the state’s labor and bargaining policies, policy wins and losses, and the perceived influence of teacher unions in the state.

The report said teacher unions across the nation are weaker than they were over a decade ago, with the percentage of teachers who are union members declining in all but four states.

In Wisconsin, membership declined from 98% in 2012 to 45% in 2025, a nearly 54 percentage point decrease and the largest drop in membership nationwide. The state ranked 43rd overall for union resources and membership compared to 13th in 2012.

The report attributed the decline in membership to Act 10, the state’s 2011 law signed by then-Gov. Scott Walker that essentially ended collective bargaining rights for public employee unions in Wisconsin.

In an email, Fordham Institute researcher Meredith Coffey said most of the data in the 2012 study predated the law, and it’s unlikely the initial report fully captured the effects of Act 10. She said the change in Wisconsin’s overall rank understates the impact of the law.

“In other words, the estimated change in rank between 2012 and today is arguably conservative,” Coffey said.

The study also found Wisconsin teacher unions’ financial resources are limited compared with unions in other states. After adjusting for cost-of-living differences, Wisconsin unions have the seventh-lowest annual revenues per teacher.

Wisconsin also ranked 44th for its labor and bargaining policies. Public-sector unions are limited to negotiating for raises capped at the rate of inflation under Act 10.

The report said just five states – Idaho, Missouri, Ohio, Oklahoma and Virginia – have enhanced collective bargaining rights since 2012.

Wisconsin teacher unions ranked 25th for their political involvement, specifically in elections and campaigns. In 2020 and 2022, the Fordham Institute found, the state’s teacher unions sponsored the second-highest number of state and local political ads in the nation.

About 70% of Wisconsin candidates endorsed by state-level teachers unions won their elections in 2024, according to the data.

The state’s teacher unions additionally ranked 26th in policy wins and losses, which the Fordham Institute measured by analyzing the extent to which Wisconsin policies align with union priorities.

In perceived influence, the organization ranked Wisconsin’s teacher unions 24th. Researchers said they measured this through a survey of people with knowledge of education policymaking in each state, including lawmakers, journalists, state education administrators and members of teacher unions, among others.

Overall, the study found the strongest unions are concentrated in Democrat-led, more affluent states, while the weakest are concentrated in Republican-led, poorer states.

The report said the strongest teacher unions are in Vermont, California, Massachusetts, New Jersey and Hawaii. The weakest teacher unions are in Arkansas, Oklahoma, Tennessee, North Carolina and Mississippi.