Mother of my child claimed my son on her taxes but hasn't had any income since he was born May 2023

[kkee732184]

We live together and she hasn't worked since the baby was born. I told her I was going to claim the baby but she did behind my back.

[SusanY1]

If your child's mother had no income there would have been no benefit to be gained claiming your child.  Nonetheless, if you are the one who qualifies to claim your child because you provided more than half of the child's support and the child lived with you all year, then you should print and mail your return to claim the credits associated with claiming your child on your tax return. 

Since the mom would have received no benefit from this the IRS will likely not pursue this further but if income was reported on that return and credits claimed the IRS will send letters to both of you in the latter part of the year requesting additional information in order to determine which tax return should be corrected with credits paid back to the IRS (with interest and penalties).  The IRS inquiry (and interest/penalties) can be avoided by having the mother file an amended return.

[Bsch4477]

The IRS will give the dependency to the parent with the higher AGI. If that is you, you can file by mail claiming the child and the IRS sort it out.