Why doesn't TT recognize the military max TSP contribution of $18K and instead tax me for over contribution of the $5k limit?

[SteamTrain · Accepted solution]

OK....here's the issue  (99.9% sure)..

Your TSP contribution is noted in box 12 of your W-2, with a code D,.

That's the ONLY place it is entered on a tax return...with your W-2 entries.

You entered them again in the "Traditional and Roth IRA Contributions" section....But, a TSP is NOT an IRA.  Two different species.  Go back to the IRA contributions you entered and blank-out or remove that entry.