International students in the United States may or may not be considered tax residents, depending on their circumstances and the duration of their stay there. The determination of tax residency for international students is based on the IRS’ substantial presence test. Tax residency for an F-1 student is determined by whether they’re considered resident aliens or non-resident aliens, so the country of tax residence for international students could be regarded as the US or the student’s home country.
J-students are not classified as non-students but non-degree visiting students whose purpose in the US may primarily focus on work-related activities. This may subject them to paying taxes to the US government.