If you are claiming your son on your tax return as your dependent, he will not be able to claim himself on his own tax return. Given that, you son can earn up to $6,300 in 2016 before being required to file a tax return. So if the $5,000 is his only income for 2016, he is not required to file a tax return. If taxes were withheld from his pay, he may want to file in order to have the taxes that were taken out refunded back to him. He would just file a 1040EZ tax form if all he had was that $5,000.