Nick Cassavetes Wins Custody of Daughter Barbie

Nick Cassavetes has won a major victory -- he has his child back after claiming his baby mama stole their child from him ... TMZ has learned.

Nick appeared in an Oklahoma courtroom Friday to square off with Heather Wahlquist over 12-year-old Barbie. Wahlquist was asking the judge for an emergency order to allow her to keep Barbie in her custody, despite the fact that it's a California case. The Oklahoma judge rejected her request.

Nick has claimed Heather and her mother essentially stole Barbie and went on the run, despite the fact that the California custody order gave him physical custody effective December 18.

Barbie went back into chambers with the judge for about a half hour, and after their talk the judge told Nick he was the one who had current lawful custody, so they left the courtroom together.

The famed "Notebook" director tells TMZ Barbie is back in L.A. with him.

Heather had claimed Nick neglected Barbie while he had custody and she returned recently with a bacterial infection. She made other claims as well but the Oklahoma judge rejected them.