Terrence Stephen Gathercole AM (25 November 1935 – 30 May 2001), was an Australian breaststroke swimmer of the 1950s and 1960s, who won a silver medal in the 4x100-metre medley relay at the 1960 Summer Olympics.

[1] Gathercole reached the peak of his swimming career in 1958 when he set the world record for the 200-metre breaststroke at the Tobruk Pool in Townsville, Queensland.

Gathercole's final appearance on the international arena as a swimmer was at the 1960 Summer Olympics in Rome, where he won his semifinal of the 200-metre breaststroke.

Gathercole then combined with David Theile, Neville Hayes and Geoff Shipton to claim silver in the 4 × 100 m medley relay, again behind the Americans.

In December 1960, he became a full-time professional coach and built an indoor short course pool in Castle Cove, New South Wales, a northern suburb of Sydney.

By 1966 Gathercole gained the contract as Head Coach at Victoria Park Swimming Pool in Sydney, which he held until 1969, when it was handed over to John Gregory.