The Green Card Test (GCT) is a criterion used by the Internal Revenue Service (IRS) in the United States to determine whether an individual qualifies as a "resident for tax purposes". The GCT asks whether, during the calendar year, an individual spent at least one day in the US as a lawful permanent resident (i.e. possessed a green card). In particular, it is not required to possess a green card when the individual files a return. The GCT is used alongside the Substantial Presence Test; specifically, an alien is considered a "resident for tax purposes" if they pass either the GCT or the Substantial Presence Test.