Reinier de Ridder, known as “The Dutch Knight,” is a Dutch mixed martial artist who has established himself as one of the world’s most accomplished middleweights in both ONE Championship and the UFC[1][3]. Born on September 7, 1990, in the Netherlands, de Ridder stands 6 feet 4 inches tall and competes in the middleweight division, currently representing the Combat Brothers team[4]. He is recognized for his southpaw stance, technical grappling, and a finishing rate that has made him a standout in multiple promotions[3][4]. De Ridder’s early career was marked by a strong foundation in martial arts and a relentless work ethic, shaped by his upbringing in a small town outside Tilburg[3]. He turned professional in 2013 and built his reputation in regional European circuits before joining ONE Championship, where he rapidly ascended to global prominence[6]. In ONE, he captured both the middleweight and light heavyweight titles, notably defeating two-division champion Aung La N Sang in October 2020 to claim the middleweight belt—a victory that cemented his status as a top-tier fighter[3][8]. His reign in ONE was characterized by a dominant, submission-heavy style and an undefeated streak that drew international attention[3][8]. After a high-profile run in ONE Championship, de Ridder transitioned to the UFC, making his debut in 2024 after a period of legal and promotional challenges[6]. His UFC journey has been closely watched, with notable fights including a high-stakes bout against former champion Robert Whittaker, which he won by split decision, and a recent headline match against Brendan Allen in October 2025, though the latter ended with de Ridder retiring in his corner[1]. These performances have kept him relevant in the UFC’s competitive middleweight division, where he remains a contender to watch[1]. Outside the cage, de Ridder is a dedicated family man and entrepreneur, owning a gym in the Netherlands and prioritizing time with his two young children[2]. His ability to balance professional ambition with personal life has been a consistent theme in interviews, reflecting a grounded perspective amid the pressures of elite combat sports[2]. As of late 2025, Reinier de Ridder continues to compete at the highest level, with his career trajectory, championship pedigree, and recent high-profile fights ensuring his ongoing significance in global MMA[1][6].