is it taxable if PhD student accepts teaching assistantship with full waiver & stipend

It’s actually the opposite for undergrads(all students?), @billcsho . Schools are not required to send the 1098t if the scholarships exceed the tuition and fees. It is bassackward for paying taxes on your taxable scholarship as you DON’T get a notice that you have taxable scholarship but DO get the 1098T if your tuition exceeds scholaships, so you might get a credit.

I used Tax Act and it asked about the 1098t, other payments received, if any of the money received was for teaching or other work. I think it is common for some of the money to be on the different tax forms, 1098t or 1099, or aa W2.