Stop Taxpayer Funding of Hamas Act This bill prohibits obligating or expending U.S. funds in Gaza unless the President makes certain certifications. Specifically, it prohibits such expenditures unless the President certifies that (1) the funds will not benefit Hamas, Palestinian Islamic Jihad, other foreign terrorist organizations, or their members; and (2) all hostages taken by such organizations have been freed. The bill also prohibits obligating or expending funds in Gaza through any United Nations entity or office unless the President certifies that the entity or office is not encouraging or teaching anti-Israel or anti-Semitic ideas or propaganda.