It was launched in September 2000, and publishes new material (usually some combination of fiction, articles, reviews, columns, poetry, and/or art) 51 weeks of the year. The magazine was founded by writer and editor Mary Anne Mohanraj. It has a staff of approximately thirty volunteers, and is unusual among professional speculative fiction magazines in being funded entirely by donations, holding annual fund drives.
Susan Marie Groppi won the World Fantasy Special Award: Non-Professional in 2010 for her work as Editor-in-Chief on Strange Horizons,. The the magazine itself was nominated for the Best Website Hugo Award in 2002 and 2005, and for the Best Semiprozine Hugo Award in 2013 and 2014.
The short story "The House Beyond Your Sky" by Benjamin Rosenbaum, published in 2006 in the magazine, was nominated for a 2007 Hugo Award for Best Short Story. The story "Selkie Stories Are For Losers" by Sofia Samatar was nominated for a Hugo Award for Best Short Story in 2014. Other stories in Strange Horizons have also been nominated for the Nebula and other awards; stories from Strange Horizons have won the last two Theodore Sturgeon Awards.