Pennefather is a surname. Notable people with the surname include:
David Pennefather CB OBE (born 1945), former Royal Marines officer, became Commandant General Royal Marines
Edward Pennefather PC, KC (1775–1847), Irish judge
Joan Pennefather, Canadian film and cultural executive
John Lysaght Pennefather GCB (1798–1872), British soldier who won two very remarkable victories
Sir John Pennefather, 1st Baronet JP (1856–1933), British cotton merchant and Conservative politician
Owen Edward Pennefather Lloyd VC KCB (1854–1941), Irish recipient of the Victoria Cross
Richard Pennefather, the 9th Attorney-General of Western Australia
Richard Pennefather (judge) (1773–1859), Irish judge, praised for his conduct of the Doneraile Conspiracy Trials of 1829
Rupert Pennefather, principal dancer in the Royal Ballet Company
