Why cannot I deduct my son's college tuition (he is my dependent)? Can you make too much income to deduct tuition?

Yes, if your income is to high then you won't qualify for the Education Credits or the Tuition Deduction. 

For the American Opportunity Tax Credit to get the fill credit your 2020 MAGI (modified adjusted gross income) must be less than $90,000 ($180,000 if you're filing jointly). For a reduced credit, your MAGI must between $80,000 and $90,000 ($160,000 and $180,000 if you're filing jointly).

For the Lifetime Learning Credit your 2020 MAGI (modified adjusted gross income) must be less than $59,000 ($118,000 if you are filing jointly). For a reduced credit, your MAGI must be between $59,000 and $69,000 ($118,000 and $138,000 if you're filing jointly)

For the Tuition and Fees Deduction your AGI (adjusted gross income) must be less than $80,000 ($160,000 if you are filing jointly).

Please see What education tax credits are available? , Who is eligible to take the American Opportunity Tax Credit? , Who is eligible for the Lifetime Learning Credit? and What is the Tuition and Fees Deduction?  for additional information.

If you are below the MAGI limits then you might have to review your entries. Please review each question carefully:

1. Login to your TurboTax Account 
2. Click on the Search box on the top and type “1098T”
3. Click on “Jump to 1098T”

[Edited 2/13/2021 | 8:01am PST]