Sir Robert Cosgrove KCMG (28 December 1884 – 25 August 1969) was an Australian politician who was the 30th and longest-serving Premier of Tasmania.

His involvement in state politics spanned five decades, and he dominated the Tasmanian branch of the Australian Labor Party for a generation.

Cosgrove attended state schools in Campania, Sorell, and Richmond, before completing his education at St Mary's College, Hobart.

[1] When Albert Ogilvie died suddenly in 1939, 68-year-old Edmund Dwyer-Gray was elected Labor leader (and thus premier) with the understanding that he would retire after six months in office.

[1] During World War II, Cosgrove co-operated closely with the federal government, particularly under Labor prime ministers John Curtin and Ben Chifley.

[1] Cosgrove led his party to a significant victory at the 1941 state election, which saw Labor win 20 out of 30 seats.

He stood down as Premier during his trial, and longtime minister Edward Brooker was sworn in as his replacement on 19 December 1947.

He retired as premier on 25 August 1958, at the age of 73, and was replaced by his long-serving deputy Eric Reece, who kept Labor in power until 1969.

He was also a member of the council of the University of Tasmania (1940–46 and 1948–55) and of the local branch of the St Vincent de Paul Society, and president of the Royal Hobart Golf Club.