Gilbert Joshua Spencer-Smith JP (17 December 1843 – 2 February 1928) was an English first-class cricketer and British Army officer.

Spencer-Smith was born at Brooklands, the Spencer-Smith family home in December 1843; he was a twin, born alongside Orlando Spencer-Smith.^[1] His parents were Spencer Smith and Frances Anne Seymour.^[2] He was educated at Eton College,^[3] where he played for the college cricket team which was captained by Mike Mitchell.^[1] After completing his education, Spencer-Smith chose to pursue a career in the British Army and purchased the commission of ensign in the 25th Foot in March 1863.^[4] He played first-class cricket for Hampshire in their first season as a first-class county in 1864, making one appearance against Sussex at Hove.^[5] Opening the batting in both Hampshire innings, he was dismissed twice by James Lillywhite for scores of 11 and 9.^[6] He was described by Wisden as "a good slow round-armed bowler, and quick at short slip."^[1]

In October 1865, he purchased the rank of lieutenant while serving in the 85th Foot,^[7] before purchasing the rank of captain in October 1871.^[8] He retired from active service in January 1876, while retaining the rank of captain,^[9] but returned to service with the Royal Hampshire Regiment in April 1877.^[10] He later retired his commission with the Royal Hampshire Regiment in April 1886 and was granted the honorary rank of major.^[11] A justice of the peace for Hampshire,^[3] Spencer-Smith died at Bursledon in February 1928.^[1] His twin brother was also a first-class cricket, as were his nephew Cunliffe Gosling and uncle Henry Wilder.