Katherine "Kat" Westbury (Thai: แคทเธอรีน เวสบุรี; born 14 March 1993) is an inactive Thai-New Zealand tennis player.

Aged three she moved to Bangkok, Thailand with her parents where she attended pre-school and primary school.

Having played doubles in just one previous ITF tournament, and that being six years earlier, Westbury was awarded a wildcard into the Auckland Open with Rosie Cheng; they were beaten by Petra Martić and Anna Tatishvili in the first round.

Westbury resumed her professional career in 2020, starting at the reintroduced ITF tournament in Hamilton.

Westbury played one Billie Jean King Cup (formerly Fed Cup) match for New Zealand in April but, more importantly, won her first professional title when partnering Destanee Aiava to win an ITF doubles title in Traralgon, Australia, at the end of November.