I was able to claim my daughter as a dependent even though she only lived with me for two months. Is this legit or is this a mistake?

[npierson7]

It depends. The non-custodial parent can claim the child as a dependent if the custodial parent agrees not to on their own tax return. However, you must obtain a signed IRS Form 8332 or similar written document from the custodial parent allowing you to do so. 

[rickvanschoyck]

I am the custodial parent as her mother is deceased. She turned 18 in March and moved out of the house. Is she still eligible as my dependent after just two months?

[DMarkM1]

No, probably not.  Be sure you have answered all the dependent questions in TurboTax that describe your situation.   

How many months did the child live with you in the US?  Three

Did the child provide over half of her support?  Yes  (since she was on her own for more than 1/2 the year).

Either of these answers would disqualify her as your dependent child under rules 3 and/or 4.   

1. The child must be your son, daughter, stepchild, foster child, brother, sister, half brother, half sister, stepbrother, stepsister, or a descendant of any of them.

2. The child must be (a) under age 19 at the end of the year and younger than you (or your spouse if filing jointly), (b) under age 24 at the end of the year, a student, and younger than you (or your spouse if filing jointly), or (c) any age if permanently and totally disabled.

3. The child must have lived with you for more than half of the year.

4. The child must not have provided more than half of his or her own support for the year.

5. The child must not be filing a joint return for the year (unless that joint return is filed only to claim a refund of withheld income tax or estimated tax paid).

Additionally you would probably answer the question did you provide over 1/2 of her support?  No 

That would disqualify her as a dependent relative under rule 4 below.  Plus she probably made over $4300 for the year (rule 3).

1. The person can't be your qualifying child or the qualifying child of any other taxpayer.

2. The person either (a) must be related to you in one of the ways listed under Relatives who don't have to live with you , or (b) must live with you all year as a member of your household (and your relationship must not violate local law).

3. The person's gross income for the year must be less than $4,300.

4. You must provide more than half of the person's total support for the year.