You can claim the child if she lives with you** and does not live with her father. Child support is not relevant.
If someone else claimed your dependent inappropriately, and if they file first, your return will be rejected if
e-filed. You would then need to file a return on paper, claiming the
child as appropriate. The IRS will process your return and send you
your refund, in the normal time. Shortly (up to a year) thereafter, you'll receive
a letter from the IRS, stating that your child was claimed on another return.
It will tell you that if you made a mistake to file an amended return and if
you didn't make a mistake to do nothing. The other party will get the same letter
you did. If one of you doesn't file an amended return, unclaiming the child,
the next letter, from the IRS, will require you to provide proof. Be sure to
reply in a timely manner.
If the mother lives with you and she has given the father permission (on IRS form 8332) to claim the child; then you cannot claim the child.
**Full rules
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, 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.
.A child closely related to a taxpayer can be a
“Qualifying Child (QC)” dependent, regardless of the child's income, if:
1.
He is under age 19, or under 24 if a full time
student for at least 5 months of the year, or
is totally & permanently disabled
2.
He did not provide more than 1/2 his own
support
3.
He lived with the relative (including temporary
absences) for more than half the year
4.
He is younger than the relative (not applicable
for a disabled child)
5.
If the
child meets the rules to be a qualifying child of more than one person, you
must be the person entitled to claim the child as a qualifying child (this
essentially means that you have the parent’s permission to claim the child, if the child also lived with the
parent more than half the year)
6.
If the parents of a child
can claim the child as a qualifying child but no parent so claims the child, no
one else can claim the child as a qualifying child unless that person's
adjusted gross income (AGI) is higher than the highest AGI of any of the child's
parents who can claim the child. This means if the child's parent lives with you, you must have a higher income than that parent to claim the child. You do NOT need to have a higher income than the parent (the father) that does not live with you.
https://turbotax.intuit.com/tax-tools/tax-tips/Family/Rules-for-Claiming-a-Dependent-on-Your-Tax-Ret...
