Mark Schwahn is an American former screenwriter, director, and producer. He is best known as the creator of the WB/CW teen drama series One Tree Hill. His career abruptly ended in 2018 due to widespread sexual harassment accusations by the show's female cast and crew members during its production.

One Tree Hill is an American drama television series created by Mark Schwahn, which premiered on September 23, 2003, on The WB. After the series' third season, The WB merged with UPN to form The CW, and from September 27, 2006, the series was broadcast by The CW in the United States until the end of its run in 2012. The show is set in the fictional town of Tree Hill, North Carolina, and initially follows the lives of two half-brothers, Lucas and Nathan Scott, who compete for positions on their school's basketball team and the drama that ensues from the brothers' romances.