Loek Postma (born 5 March 2003) is a Dutch professional footballer who plays as a centre-back for club RKC Waalwijk.
Postma moved from his home-town club FC Uitgeest to the academy of AZ in 2014. He was awarded his first professional contract with AZ in June 2021. The deal was for 3 years with the option of a fourth. Postma made his league debut on 22 April 2022 in a 3-3 draw with Excelsior Rotterdam in the Eerste Divisie at the Stadion Woudestein. On 3 November 2023, he scored his first league goal with an injury time equaliser in a 2-2 draw away at VVV Venlo.
On 8 August 2024, Postma signed a two-year contract with Vitesse.
On 21 August 2025, Postma moved to RKC Waalwijk on a three-season deal.