Pleshette was born on January 31, 1937 in Brooklyn Heights, Brooklyn, New York to Eugene Pleshette and Geraldine (née Kaplan) . Her parents were Jewish, the children of emigrants from Russia and Austria-Hungary. Her mother was a dancer and artist who performed under the stage name Geraldine Rivers. Her father was a stage manager, manager of the Paramount Theater in New York City, manager of the Paramount Theater in Brooklyn, and later, a network executive. She graduated from Manhattan's High School of Performing Arts and attended Syracuse University for one semester before transferring to Finch College. She later graduated from Manhattan's prestigious acting school, the Neighborhood Playhouse School of the Theatre and was under the tutelage of renowned acting teacher Sanford Meisner.