Roel Mannaart (born 10 February 1994) is a Dutch kickboxer. He is a former K-1 WORLD GP Heavyweight Champion. He also competed for Glory.
Mannaart was ranked as a top ten heavyweight by Combat Press between July 2019 and July 2021, peaking at #7.
Manaart beat Semmie Onoiafie at Fighting Rookies in May 2016. He won the fight by a second round TKO. He would notch up three more wins in the Dutch circuit, defeating Michael Lorenz, Thomas Bridgewater and Nico Pereira Horta.
Mannaart participated in the 2017 K-1 Heavyweight Grand Prix, being scheduled to fight Masahiro Iwashita in the quarterfinals. He beat Iwashita by a first round knockout, but lost to Ibrahim El Bouni by knockout in the semifinals.
Four months later, Mannaart was scheduled to fight Antonio Plazibat for the K-1 Heavyweight title at . Roel won the fight by unanimous decision.
Mannaart subsequently signed with Glory as well, and fought Daniel à  kvor at . He beat Skvor by unanimous decision. In his next fight with Glory, Mannaart was scheduled to fight Kirill Kornilov, whom he beat by unanimous decision.
Mannaart was scheduled to defend his K-1 title against Chris Bradford, at K-1 World GP 2019 Yokohamatsuri. He knocked Bradford out in the first round.
Roel Mannaart returned to Glory at to fight Sergej Maslobojev. Maslobojev won the fight by a first round TKO, with Mannaart suffering a broken jaw during the bout.
Following the loss to Maslobojev, Mannaart returned to K-1 to defend his Heavyweight title in July of 2025. He would face former K-1 Cruiserweight champion, K-Jee. Mannaart won the fight via KO in the second round, dropping K-Jee multiple times, before finishing him with low kicks.
|- style="text-align:center; background:#fbb" | 2025-11-15|| Loss||align=left| Ariel Machado || K-1 World MAX 2025 - 70kg World Championship Tournament Final || Tokyo, Japan || TKO (Punches)|| 1||3:00 |- ! style=background:white colspan=9 |
|- style="text-align:center; background:#cfc;" | 2025-07-13 || Win || align=left| K-Jee || K-1 Dontaku || Fukuoka, Japan || KO (Low kicks) ||2 ||1:32 |- ! style=background:white colspan=9 | |- style="text-align:center; background:#fbb;" | 2020-02-29 || Loss || align="left" | Sergej Maslobojev || || Utrecht, Netherlands || TKO (Corner stoppage) || 1 || 1:48
|- style="text-align:center; background:#cfc;" | 2019-11-24 || Win|| align=left| Chris Bradford|| K-1 World GP 2019 Yokohamatsuri || Yokohama, Japan || KO (Punches)|| 1 || 2:19 |- ! style=background:white colspan=9 |
|- style="background:#cfc;" |- align="center" bgcolor="#cfc" | 2018-12-08 || Win ||align=left| Kirill Kornilov || || Rotterdam, Netherlands || Decision (Unanimous) || 3 || 3:00
|- align="center" bgcolor="#CCFFCC" | 2018-09-29 || Win ||align=left| Daniel à  kvor || || Amsterdam, Netherlands || Decision (Unanimous) || 3 || 3:00
|- align="center" bgcolor="#CCFFCC" | 2018-03-21 || Win || align=left| Antonio Plazibat || || Saitama, Japan || Decision (Unanimous) || 3 || 3:00 |- ! style=background:white colspan=9 |
|- align="center" bgcolor="#FFBBBB" | 2017-11-23 || Loss ||align=left| Ibrahim El Bouni || K-1 World GP 2017 Heavyweight Championship Tournament, Semi Finals || Saitama, Japan || KO (Uppercut) || 1 || 3:00
|-align="center" bgcolor="#CCFFCC" | 2017-11-23 || Win ||align=left| Masahiro Iwashita || K-1 World GP 2017 Heavyweight Championship Tournament, Quarter Finals || Saitama, Japan || KO (Left hook) || 1 || 2:47
|- style="background:#cfc;" | 2017-05-27 || Win ||align=left| Nico Pereira Horta || Rings Fighting Network || Amstelveen, Netherlands || Decision (Unanimous) || 3 || 3:00
|- style="background:#cfc;" | 2017-04-08 || Win ||align=left| Rinor Latifaj || Road 2 Victory Sokudo || Hoorn, Netherlands || TKO (Doctor stoppage) || 2 ||
|- style="background:#cfc;" | 2017-02-18 || Win ||align=left| Taoufik Benhaddou || Battle Under the Tower || Steenwijk, Netherlands || Decision (Unanimous) || 3 || 3:00
|- style="background:#cfc;" | 2016-10-22 || Win ||align=left| Thomas Bridgewater || RINGS Beverwijk 2016 || Beverwijk, Netherlands || TKO (Corner stoppage) || 3 ||
|- style="background:#cfc;" | 2016-06-04 || Win ||align=left| Michael Lorenz || Day of Destruction 11 || Hanover, Germany || KO (Body kick) || 1 || 1:40
|- style="background:#cfc;" | 2016-05-22 || Win ||align=left| Semmie Onoiafie || Enfusion Fighting Rookies || Amsterdam, Netherlands || TKO || 2 ||
|- style="background:#cfc;" | 2016-02-13 || Win ||align=left| Patrick Dierichsweiler || Rissing Sun 2.0 || Beilen, Netherlands || TKO (Retirement) || 2 || 3:00
|- style="background:#cfc;" | 2015-10-17 || Win ||align=left| Levi Rigters || Ultimate Kickboxing || Hoogeveen, Netherlands ||Decision || 3 || 3:00
|- style="background:#cfc;" | 2015-06-06 || Win ||align=left| Ali dos Passos || RingFight - Heavyweight Tournament, Final || Eindhoven, Netherlands || Decision || 3 || 3:00
|- style="background:#cfc;" | 2015-06-06 || Win ||align=left| Abderrahman Barkouch || RingFight - Heavyweight Tournament, Semifinal || Eindhoven, Netherlands || Decision || 3 || 3:00
|- style="background:#cfc;" | 2015-04-18 || Win ||align=left| Piotr Mlinski || Day of Destruction 10 || Hamburg, Germany || TKO (Corner stoppage) || 3 || 0:52
|- style="background:#cfc;" | 2014-09-28 || Win ||align=left| André Agbobly || WLF Mejiro || Netherlands || Decision || 3 ||
|- style="background:#cfc;" | 2014-03-15 || Win ||align=left| Fabian Heil || Fight For Victory V || Netherlands || Decision || ||
|- | colspan=9 | Legend: