In my W-2 Form in box 12 I have "AA 16" but in the options given in TurboTax it only says "AA for 401k" but my contributions have been to TSP... Is it the same thing?

[dmertz]

Select code AA.  With regard to this contribution, the TSP follows the same rules as a 401(k).  Ignore the "16" since code AA by itself means a contribution for 2016 by default.