Only one parent claim the dependency and that parent is the one with whom the child lives.  It doesn’t matter that you pay the education expenses. But if your ex wife wanted she could let you claim her by giving you a signed Form 8332. 

Only the parent claiming the dependent can claim the education credit  or deduction.  Your ex wife may claim the credit, even though you paid the tuition. Educational expenses  are an exception to the general rule that you may only deduct what you actually pay. 

EDIT Note: see the comments about "emancipation" at the other replies.

There is a way to split the tax benefits.  This may be helpful in your negotiations with the ex:

 There is a special rule in the case of divorced & separated (including never married) parents. When the non-custodial parent is claiming the child as a dependent/exemption/tuition credit; the custodial parent is still allowed to claim the same child for Earned Income Credit, Head of Household filing status, and day care credit. This "splitting of the child" is not available to parents who lived together at any time during the last 6 months of the year; then only one of you can claim the child for any tax reasons. The tax benefits may not be split in any other manner.

Note in particular that the non-custodial parent can never claim the Earned Income Credit, Head of Household filing status or the day care credit, based on that child, even when the custodial parent has released the dependency to him.

 So, it's good idea to let the other parent know that you will be claiming those items, as many first time divorced parents are not aware of this rule and may try to claim those items, which will cause the IRS to send out letters.

Ref: https://www.irs.gov/publications/p17#en_US_2017_publink1000170897

Scroll down to "Children of divorced or separated parents (or parents who live apart)"

You can if you are the custodial parent.  The custodial  parent is the parent the child lived with for more than 182 nights in 2019.

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@bruce2020 wrote:

 

My daughter turned into 18 and went to college in year 2020. 

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I just want to clarify the previous comments about the ability of your ex-wife to allow you to claim your daughter as a dependent.  That option may not be available.

In most states, when a child turns age 18 they are considered emancipated from their parents, and the restricts the ability for your ex-wife to allow you to claim daughter (assuming your daughter does not live with you).  Unless your daughter was less than 18 for over half of the year, that option is not  available.

If your daughter is under age 24 and a full time student and doesn’t provide more than half of her support she can be claimed by her mother assuming she lives with her. 

My daughter just turned 18 at Feb 2020. she went to college as full time student and live on the campus. so she is not live with me or her mother.

Hello Hal_AI,

My daughter is over 18 and full time student who lives on the campus. I am an non-custodial parent. I am not live with ex-wife. Base on the special rule, my understanding is that I can claiming my daughter as dependent only for tuition credit. I paid for 12K so far this year. I am wondering how much can I claim as deductible ? what should I tell my ex-wife? could she also claim her portion of tuition credit?

please advise?

Thank you

Thank you!

Time away at school is considered as being home. If she lived with her mother until going to school and if she would return there for vacations and the summer that is her home. 

Your daughter usually lived with her mother, and unless there is solid evidence that your daughter has PERMANANTLY moved away from her mother's house, she is considered as living with her mother.  That gives her mother the right to claim her as a dependent (assuming your daughter did not pay for over 1/2 of her own support).

Your daughter was over 18 for over 1/2 of the year.  That means in MOST states she is 'emancipated' from her parents, which means there is NOT an option for her mother to allow you to claim your daughter as a dependent (assuming your state law is age 18).   That means you can NOT claim your daughter as a dependent, which means you can NOT claim any college related credits on your tax return for her.  You can NOT claim anything in regards to your daughter on your tax return.

If the mother is claiming her as a dependent, the mother can claim the college credits on her return, including the amount based on the $12,000 that you paid.  If the $12,000 that you paid increased the credit that the mother receives, you may try asking her to share part of the refund that she receives.  But she is under no obligation to do so.