When Canadian women’s tennis player Bianca Andreescu defeated Serena Williams in a stunning upset in the 2019 U.S. Open, she probably wasn’t thinking about how that affected her taxes. But she should. Given the growth of the sports industry not only within North America, but also internationally, it is increasingly critical that foreign athletes and entertainers become educated regarding the United States’ taxation of their income. U.S. Taxation of Foreign Athletes and Entertainers Taxation of Foreign Athletes and Entertainers as Resident Aliens The first step in determining the U.S. taxation of a so-called “foreign” athlete or entertainer (namely an athlete that is not a U.S. citizen) is residency for tax purposes — specifically, whether the athlete or entertainer is a “resident alien” or a “nonresident alien.” Resident aliens, as opposed to nonresident aliens, are subject to U.S. tax on their worldwide income. Nonresident aliens, by contrast, are typically subject only to tax on income that can be “sourced” in the U.S.