I am a grad student in the social sciences, and the vast majority of my tuition is waived, as long as I TA or RA at least half time during the year. I am also paid a stipend for my TA/RA work.
From what I've read, I believe that the tuition waiver should not count as taxable income, but I wanted to make sure.
In general, yes, the tuition waiver itself is not taxable income. Stipends or TA salaries, etc. will be taxable. See this IRS information which says in part:
A scholarship or fellowship is tax free (excludable from gross income) only if you are a candidate for a degree at an eligible educational institution. [...]
Qualified education expenses. For purposes of tax-free scholarships and fellowships, these are expenses for: Tuition and fees required to enroll at or attend an eligible educational institution [...]
