Robert Roy McGregor (7 February 1907 – 5 September 2000), was an American submarine commander during World War II who reached the rank of Rear Admiral in the United States Navy.

[12] While attending submarine school at New London, McGregor and two other officers were injured when a torpedo motor they were working on exploded.

[13] McGregor was promoted to Lieutenant Junior Grade in June 1932 and upon completion of submarine school was assigned to the USS S-14 (SS-119).

[16] While assigned to R-4, he became qualified to command submarines and was transferred to the Third Naval District in New York where he was promoted to the rank of Lieutenant.

[2] Her late father was a commander in the USN Construction Corps and had been stationed at the New York Navy Yard.

On 21 September, off the coast of Shanghai, McGregor made his first kill, sinking the Japanese transport Tone Maru.

[23] Grouper arrived in Midway on 21 October, credited with 12,000 tons of enemy freight sunk, for which McGregor was awarded the Silver Star for "conspicuous gallantry and intrepidity in action".

McGregor waited until the last destroyers were passing, but an Allied air raid on the convoy caused his target to alter course, ruining his chance to attack.

On 9 February, McGregor received orders to rescue 1LT Lawrence R. McKulla, a pilot who had been shot down 26 January and was stranded on Rengi Island.

[26][28] Grouper continued its patrol, gathering intelligence on Japanese radar stations, and arrived in Brisbane on 18 March.

Two skippers who felt the lash were Dick Lake in Albacore and Rob Roy McGregor in Grouper"[29] Fife's report on Grouper's fourth war patrol was particularly harsh, claiming McGregor had not been aggressive enough, causing him to miss a golden opportunity.

The Navy seemingly took back its punitive action against McGregor,[citation needed] as in March 1945 he was awarded a second Silver Star for his second patrol commanding Grouper.

[25] Rear Admiral McGregor retired to Coronado, California in February 1957, after 28 years of naval service.

[35][25] He ran a small business in San Diego and also worked as a technical advisor on the Hollywood movie, Run Silent, Run Deep, in which he gave the scriptwriter and actors accurate details of the speech and appearance of submariners and their weaponry.