Louis Sachar (pronounced Sacker; born March 20, 1954) is an American young-adult mystery-comedy author. He is best known for the Wayside School series and the novel Holes.

Holes won the 1998 U.S. National Book Award for Young People's Literature and the 1999 Newbery Medal for the year's "most distinguished contribution to American literature for children." In 2013, it was ranked sixth among all children's novels in a survey published by School Library Journal.

Louis was born in East Meadow, New York, in 1954. When he was nine, he moved to Tustin, California. He attended the University of California at Berkeley and graduated in 1976, as an economics major. The next year, he wrote his first book, Sideways Stories from Wayside School. He was working at a sweater warehouse during the day and wrote at night. Almost a year later, he was fired from the job and decided to go to law school.

He attended Hastings College of the Law in San Francisco and graduated in 1980. For the next eight years, he worked part-time as a lawyer and continued to pursue his writing career.