If you are the custodial parent and do not want the noncustodial parent to claim the dependency exemption for your child or children, you can do one of the following:
Withhold form 8332 from the noncustodial parent.
Revoke your previous release of the dependency exemption using form 8332.
Include a provision in your divorce or separation agreement stating that the noncustodial parent cannot claim the dependency exemption for your child or children.