Her second husband was oilman Tom Gallagher, to whom she was married from 1968 until his death from lung cancer on January 21, 2000. She suffered a miscarriage during her marriage to Gallagher, and they were childless. Asked about children in an October 2000 interview, Pleshette stated: "I certainly would have liked to have had Tommy’s children. But my nurturing instincts are fulfilled in other ways. I have a large extended family; I'm the mother on every set. So if this is my particular karma, that's fine."
