Reinier de Ridder

Nationality

The Netherlands

Born

1990-09-07

Height

6'4"

Weight

185 lbs

Reinier de Ridder (born September 7, 1990), also known by his initials RdR, is a Dutch professional mixed martial artist. He currently competes in the Middleweight division of the Ultimate Fighting Championship (UFC). He previously competed in ONE Championship, where he is a former ONE Middleweight World Champion and ONE Light Heavyweight World Champion. De Ridder was the third two-division champion in ONE history, having previously held the middleweight and light heavyweight belts simultaneously. As of October 21, 2025, he is #8 in the UFC middleweight rankings. Background Reinier de Ridder started with Judo at the age of six and earned a black belt in his teens. After high school he began training in Brazilian Jiu-Jitsu while attending college and became a black belt. He also owns a physical therapy clinic in Breda, combining his working hours with his training hours.