The mythology of the Stargate franchise is a complex and eclectic fictional backstory, which is presented as being historical, of the Stargate premise. A "rich mythology and world-building" are used to establish "a vast cosmology and an interesting alternate take on the history of Earth"; a defining feature is "its use of ancient mythology, with stories that take inspiration from multiple places around the globe". Narratives center around xeno-mythology as experienced by humans during episodic contact with alien races. Audiences across a variety of platforms - including TV series, novels, comics and movies - witness the people of Earth exploring a fictional universe using the Stargate. Species established early on in the franchise recur throughout, with one adversary often dominating a particular story arc, which can continue across several seasons.

Daniel Jackson, PhD, is a fictional character in the military science fiction franchise Stargate, and one of the main characters of the 1997 series Stargate SG-1. He is portrayed by James Spader in the 1994 film Stargate, and by Michael Shanks in Stargate SG-1 and other SG-1 derived media. Jackson is the only Stargate character to appear in all films and series in the franchise.