Her parents were William and Megsie Law.
Phyllida has two grandchildren named Gaia and Ernest.
Phyllida was married to Eric Thompson until his death in 1982.
Phyllida is the mother of actresses Sophie and Emma Thompson.
Phyllida: (On working with Stephen Fry in Kingdom) What's difficult I think is his intense ability to do everything with horrifying ease and his astonishing ability to tell stories that you want to listen to. Knowing how he can read a page and go and do it. He's such an enchanting creature.