Cosgrave is a surname. Notable people with the surname include:
Fran Cosgrave (born 1977), Irish nightclub owner
James Cosgrave (died 1936), Irish nationalist politician
John B. Cosgrave (born 1946), head of the mathematics department of St. Patrick's College
Lawrence Moore Cosgrave (1890–1971), Canadian signatory to the Japanese Instrument of Surrender at the end of World War II
Liam Cosgrave (born 1920), fifth Taoiseach of Ireland
Liam T. Cosgrave (born 1956), former Fine Gael politician in the Republic of Ireland
Michael Joe Cosgrave (born 1938), Irish Fine Gael politician
Niamh Cosgrave (born 1964), former Fine Gael party politician from Dublin, Ireland
Philip Cosgrave (died 1923), Irish Cumann na nGaedhael party politician
W. T. Cosgrave (1880–1965), Irish politician
Liam Cosgrave (born 2000), Ophir Rugby Player
