Reinier de Ridder


Reinier de Ridder, 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. He previously competed in ONE Championship, where he is a former Middleweight World Champion">Middleweight (MMA)">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.

Grappling career

De Ridder won a silver medal at the European Jiu-Jitsu Championship in 2016.
De Ridder returned to submission grappling competition at ONE X on March 26, 2022 against André Galvão. The match went the distance and as the promotion did not use judges for their submission grappling matches at the time, it was declared a draw.
De Ridder faced Tye Ruotolo in a submission grappling superfight at ONE Fight Night 10 on May 5, 2023. He lost the match by a close decision.

Mixed martial arts career

Early career

De Ridder had his first amateur fight in 2013, winning by first round submission, before making his professional MMA debut later that year, winning with a first round triangle choke. Reinier went on a seven fight winning streak with all the fights ending with stoppages. After this winning streak, Reinier got the opportunity to fight for his the Middleweight belt in HIT FC, which he won by first round rear-naked choke. After winning his next bout in under two minutes, Reinier got offers from the UFC and ONE FC, deciding to go with the latter due to better terms.

ONE Championship

De Ridder made his ONE debut at ONE: Hero's Ascent on January 25, 2019 against Fan Rong, in a fight which he won by a first round submission. He would then face Gilberto Galvao at ONE: Legendary Quest, knocking out Galvao in the second round with knees, and former title contender Leandro Ataides at ONE: Warrior's Code, in which he won a hard fought decision.

ONE Middleweight Champion

De Ridder faced Aung La Nsang for the ONE Middleweight World Championship at ONE: Inside the Matrix on October 30, 2020. He won the bout by submission in the first round, becoming the champion.

Double champion

After Vitaly Bigdash tested positive for COVID-19, De Ridder stepped in for a rematch against Aung La Nsang for the ONE Light Heavyweight World Championship at ONE on TNT 4 on April 28, 2021. He won the fight by unanimous decision to become the new ONE Light Heavyweight World Champion, and the third simultaneous two-division champion in ONE history.
In the first middleweight title defense, De Ridder faced Kiamrian Abbasov at ONE: Full Circle on February 25, 2022. After applying an arm-triangle choke at the end of the second round that forced Abbasov to tap after the bell, De Ridder ultimately won with the same submission in the third round. This win earned him the Performance of the Night award.
De Ridder faced former multiple-time ADCC [Submission Fighting World Championship|ADCC] and BJJ world champion André Galvão in a grappling match at ONE: X on March 26, 2022. They grappled to a draw after 12 minutes since neither could find the submission.
De Ridder made his the second title defense against former champion Vitaly Bigdash on July 22, 2022 at ONE 159. After surviving an early guillotine from Bigdash, Reiner choked him out with an inverted triangle choke in the first round. This win earned him the Performance of the Night award.
De Ridder was scheduled to defend the middleweight title against Shamil Abdulaev at ONE on Prime Video 3 on October 22, 2022. However, Abdulaev withdrew due to not being medically cleared and the bout was cancelled.
De Ridder faced Anatoly Malykhin to defend his light heavyweight title on December 3, 2022, at ONE on Prime Video 5. He suffered his first career loss after getting knocked out in the first round.
A rematch between De Ridder and Malykhin for the ONE Middleweight World Championship took place on March 1, 2024, at ONE 166. He lost the title via technical knockout in round three.

Post ONE

After parting with the promotion, De Ridder faced Magomedmurad Khasaev on July 27, 2024 at UAE Warriors 51. He won the fight via TKO in the first round.

Ultimate Fighting Championship

On September 24, 2024, it was announced that De Ridder had signed with the Ultimate Fighting Championship.
De Ridder faced Gerald Meerschaert on November 9, 2024 at UFC Fight Night 247. He won the fight via an arm-triangle choke submission in the third round.
De Ridder faced Kevin Holland on January 18, 2025, at UFC 311. He won the fight via a rear naked choke submission in the first round.
De Ridder faced three-time NCAA Division I collegiate wrestling champion Bo Nickal on May 3, 2025 at UFC on ESPN 67. He won via technical knockout in the second round due to a knee to the body, becoming the first fighter to beat Nickal in mixed martial arts. This fight earned him his first UFC Performance of the Night award.
De Ridder faced former UFC Middleweight Champion Robert Whittaker in the main event on July 26, 2025 at UFC on ABC 9. He won the fight by split decision. 9 out of 16 media outlets scored the bout for De Ridder.
De Ridder was scheduled to face Anthony Hernandez in the main event of UFC Fight Night 262 on October 18, 2025. However, Hernandez was forced to withdraw from the bout due to an injury and was replaced by Brendan Allen. De Ridder lost the bout via technical knockout at the end of the fourth round, after he was unable to continue.
De Ridder is scheduled to face Caio Borralho on March 7, 2026 at UFC 326.

Championships and accomplishments

Mixed martial arts