Why are my HSA contributions taxable income?

were you covered by a High Deductible Health Plan for any part of 2024?

then you need to go to the medical expense section in Turbotax and complete the HSA section. until you do Turbotax will report line 12w on your W-2 as taxable income.

This is generally because you have not gone through the HSA interview (Deductions & Credits->Medical->HSA, MSA, 1099-SA) to show that you have satisfactory HDHP coverage for the HSA contributions.

Please go through the HSA interview and then see if you still have "excess contributions" (which is why your code W amount was added to Other Income).