Employee business expenses can be deducted as an adjustment to income only for specific employment categories and eligible educators.
Taxpayers can no longer claim unreimbursed employee expenses as miscellaneous itemized deductions, unless they are a qualified employee or an eligible educator. They must complete Form 2106, Employee Business Expenses, to take the deduction.
Armed Forces reservists
Qualified performing artists
Fee-basis state or local government officials
Employees with impairment-related work expenses
No other type of employee is eligible to claim a deduction for unreimbursed employee expenses.
Paid or billed during the tax year
For carrying on a trade or business of being an employee, and
Ordinary and necessary
There is a full list of nondeductible expenses in Publication 529, Miscellaneous DeductionsPDF.