I live in PA and work in NJ. My W2 box 15 specific for NJ and my employer did not withold income for PA. Do I need to file for both states?
Yes, as a Pennsylvania resident, you need to file a state income tax return.
Because you had New Jersey taxes withheld, you need to file a tax return on this state as well.
However, because these states have tax reciprocity agreement, you will report your NJ sourced income as $0 and receive a full refund for the tax withheld from your wages.
Going forward, you need to change your withholding to PA, so you will only need to file one tax return.
Follow this link for the form you need to file with your employer: