Robert William Rankin (3 June 1907 – 4 March 1942) was a Royal Australian Navy officer who was killed in action during the Second World War.

He completed the Junior Officers War Course, at Greenwich, in Britain, graduating as one of six sub-lieutenants who "received their Lordship’s appreciation of essays written".

Serving in a range of ships, in the normal style of developing his general abilities, he was promoted to Lieutenant in 1929, and ended the 1920s with a posting as Assistant Torpedo Officer in the cruiser HMAS Canberra, where he also gained his watchkeeping certificate.

He was married in that year, to Mary Broughton, a trainee nurse based on Thursday Island, in Brisbane, in a glittering affair keenly reported in the local newspapers, which featured Rankin's naval officer friends – who called him 'Oscar' – forming an "arch of swords", for their friend and his bride to walk under as they entered the reception.

Gaining a step in his survey career as Assistant Surveyor 2nd Class in July 1938, Rankin remained with Gleaner until 11 September 1939, when he was posted to the shore training establishment of HMS Dryad, for a navigating course.

His report on posting commented again in glowing terms and gave Rankin the credit for the successful esprit de corps on board.

On 5 February 1942, while under air attack near Singapore, Yarra took on board 1,804 people from the SS Empress of Asia, a troopship which had caught fire.

At 6.30am on 4 March, while escorting a small convoy from Java to Australia, Yarra encountered a Japanese naval force comprising three cruisers and two destroyers.

A group of Australian naval historians and others are campaigning Rankin to be awarded a posthumous Victoria Cross (as was awarded to Captain Edward Fogarty Fegen of HMS Jervis Bay, and to Lieutenant Commander Gerard Broadmead Roope of HMS Glowworm, for similarly defending convoys against hopeless odds).