No. Child support is not relevant to whether your can claim dependents. So even if you paid it in 2016, it would have no bearing.
See full rules for claiming dependents, below.
For your girlfriend, she must have little or no income and must have lived with you all year.
For your child, we need to know where he lived and whether your girlfriend, or some other relative in her household (e.g. the child's grandparent) wants to or can claim him.
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 a residence test. Only a QC
qualifies the taxpayer for the Earned Income Credit, the Child Tax Credit.
A child of a taxpayer can still be a “Qualifying Child” (QC) dependent, regardless of his/her 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. Scholarships are
considered third party support and not as support provided by the student.
3. He lived with the parent
(including temporary absences such as away at school) for more than half
the year; or half the time since he was born, if born in 2016.
A person can still be a Qualifying
relative dependent, if not a Qualifying Child, if he meets the 6 tests for
claiming a dependent:
1. Closely Related OR live
with the taxpayer ALL year
2. His/her gross taxable income for the year must be less than $4,050 (2016)
3. The taxpayer must have
provided more than 1/2 his support
In either case:
4. He must be a US citizen or resident of the US, Canada
or Mexico
5. He must not file a joint
return with his spouse or be claiming a dependent of his own
6. He must not be the
qualifying child of another taxpayer
