The Krelboynes are a group of gifted students at Malcolm's school. About six Krelboynes make recurring appearances. They have a hard time making non-Krelboyne friends because of their almost nonexistent popularity, and social problems. Malcolm is often called the coolest of the Krelboyne kids. Despite there being many female Krelboynes in the class, only one makes recurring appearances.
List of Krelboynes
Stevie Kenarban, played by Craig Lamar Taylor, is a Krelboyne and Malcolm's best friend. He uses a wheelchair to get around and speaks in drawn out breaths due to breathing problems.
Lloyd, played by Evan Matthew Cohen, is the overly dramatic, physically frail, and nerdy Krelboyne friend of Malcolm Wilkerson.
Kevin, played by Victor Z. Isaac, is a nervous and excitable Krelboyne friend of Malcolm.
Cynthia Sanders, played by Tania Raymonde, is a new and outgoing Krelboyne girl who moves to Malcolm's school in Season 2. Malcolm develops a crush on her when she arrives. She knows the martial art krav maga, and uses it to subdue Reese. She is absent during Season 3, as she travels to Europe with her father. She is the only Krelboyne girl to have a proper role.
Dabney Hooper, played by Kyle Sullivan, is Malcolm's emotionally stricken and flamboyant best friend for the first four seasons.
Eraserhead, played by Will Jennings, is a minor character who appears in a few episodes. He is very talented on the piano, and he also has an older brother, who defends him if he gets bullied.
Lionel Herkabe, played by Chris Eigeman, is a former Krelboyne who used to be one of the Krelboynes when he was a child. As an adult, he has become a teacher for the Krelboynes and is extremely rude and pretentious toward them.