Yes, you can, if you Itemize your deductions.
If your Union Dues are on your W-2 in Box, TurboTax will
automatically enter the union dues on Schedule A, Itemized Deductions, Line 21,
Unreimbursed employee expenses.
Unreimbursed employee expenses are subject to the 2% rule. Click
on What is the 2% rule?
For additional information on where to enter Unions dues if you
are self-employed or they are not reflected on your W-2, click on Can I deduct union dues, and where
do I enter them in TurboTax?