Penberthy is a locational surname of Cornish origin, which meant a person from Penberthy Cross in Cornwall. Notable people with the surname include:
Bob Penberthy (born 1943), British rugby playerBeverly Penberthy (born 1949), American actressBryan Penberthy (born 1976), American poetDavid Penberthy (born 1969), Australian journalistJames Penberthy (1917–1999), Australian musicianJoanna Penberthy (born 1960), Welsh Anglican bishopLarry Penberthy (1916–2001), American businessmanMike Penberthy (born 1974), American basketball playerStan Penberthy (1906–1989), Australian football playerTony Penberthy (born 1969), British cricket player