Can I claim college tuition I paid for my daughter even if she worked?

[MinhT1]

It depends.

If she is under age 24 at the end of 2020 and a full time student, you can claim her as a dependent as long as she does not provide more than half of her own support. You can then claim her education expenses on her form 1098-T and get education credits or deductions.

If she is 24 or older and/or not a full time student, then you cannot claim her as a dependent if she earned more than $4,300. Then only she can claim her education expenses.

[Hal_Al]

Q. Can I claim college tuition I paid for my daughter even if she worked?

A.  Yes, as long as she qualifies as your dependent.

Working, alone, does nor disqualify her as a dependent.  

There are two types of dependents, "Qualifying Children"(QC) and standard ("Qualifying Relative" in IRS parlance even though they don't have to actually be related). There is no income limit for a QC but there is an age limit, student status, a relationship test and residence test. Only a QC qualifies a taxpayer for the Earned Income Credit and the Child Tax Credit. They are interrelated but the rules are different for each.

The support test is different for each type. The support test, for a QC, is only that the child didn't provide more than half his own support. The support test for a Qualifying Relative is that the taxpayer provided more than half the relative's support.