Katherine "Kat" Westbury (Thai: ????????? ???????; born 14 March 1993, in Hamilton) is a Thai-New Zealand tennis player.
Westbury reached her best singles ranking of world number 576 on 3 October 2011.
She made her WTA tour debut at the 2015 ASB Classic, having received a wildcard into the doubles event with Rosie Cheng.
They were beaten by Petra Martic and Anna Tatishvili in the first round, and it was her last professional doubles match.
She has not played singles at this level since March 2015.
Westbury was born in Hamilton, New Zealand, and she has two brothers.
At age of three she moved to Bangkok, Thailand with her parents where she attended pre-school and primary school.
Westbury began playing tennis at the age of 6 at The British Club in Bangkok.
Her family returned to New Zealand two years later, settling in Christchurch, where she attended Burnside Primary School and Cobham Intermediate School, while also playing on the Canterbury Tennis Regional Squad under coach Glenn Wilson.
In 2005 the family moved to Sydney, before further re-locating to Burwood East, Victoria, where she still resides.