My employer does not cover travel it cost me about 800$/month in gas. Can I claim this cost and get reimbursed the full amount on my taxes?

[GeorgeDenseff]

You could have before 2017.  The Tax Cuts and Jobs Act suspended employee business expenses until 2025.

[rjs]

What do you mean by "travel"? If you mean commuting between your home and the job, you cannot claim a tax deduction for it. It doesn't matter how far it is or how much it costs.

The cost of commuting was never tax deductible, even before 2017 or after 2025. Commuting is not an employee business expense. It's a personal expense, and there is no tax deduction for it.

[xmasbaby0]

Are you a W-2 employee?   Commuting to or from work is not deductible on your tax return.   And, unfortunately, even if you are driving around during your work day, if you are a W-2 employee, that is not deductible either, per the tax laws that went into effect for 2018 and beyond.

https://ttlc.intuit.com/questions/4482873-which-federal-tax-deductions-have-been-suspended-by-tax-re...

[Opus 17]

If you are a W-2 employee, you can’t deduct any unreimbursed work expenses.  However, there may be state labor laws that require your employer to reimburse you.  Essentially, if you are hired for, let’s say, $1000 per week, but you have $200 of expenses that you must pay to do your job, then your pay is really only $800 per week and that arrangement might be disallowed by state law.  Check your state labor department.  But there is no tax deduction.  

If you are self-employed, let us know for more information.  Vehicle mileage may be deductible,  but it’s more complicated than just gas money.  

[Hal_Al]

Since 2018, regular W-2 employees are not allowed to deduct job expenses, including gas and mileage.  Even in the "old days" , job expenses were only a misc. itemized deduction.  You only got to deduct that portion of  your misc. itemized deductions that exceeded 2% of your AGI,  and then only if your total  itemized deductions exceeded the standard deduction (which was doubled under the 2018 tax law).

But, employers are allowed to deduct their employee's expenses, as long as they are reimbursed under an "accountable plan" (employees submit detailed expense reports).   On the other hand, if the salary you negotiated included an "allowance"  for anticipated job expenses, that allowance is taxable income to you and the expenses are not deductible.