Raised in Abington, Pennsylvania, Deborah Kaplan met her creative partner Harry Elfont while they were both enrolled at the Tisch School of the Arts of New York University (NYU). They have since written several films together, and directed two: Can't Hardly Wait and Josie and the Pussycats.

Kaplan married actor Breckin Meyer (who had small roles in both of the films she directed) on October 14, 2001. They have one child together, a daughter named Keaton Willow, born on December 31, 2003.