Do teacher union dues qualify for the Educator Expense deduction?
No; only unreimbursed expenses for books, supplies, and equipment that you purchased for classroom use qualify for the $250 Educator Expense deduction. More info
Employee union dues are no longer deductible in tax years 2018 through 2025 due to the Tax Cuts and Jobs Act (TCJA) that Congress signed into law on December 22, 2017. Prior to that, they were partially deductible as a miscellaneous deduction under the 2% rule.