The Mass Effect series is one of the most robust and fully-realized science fiction worlds ever created. With a brilliant cast of memorable characters, each with their own stakes in this epic saga to save the galaxy, Mass Effect makes the player truly feel as though they are part of a larger world where their decisions have a massive impact on the epic story. However, Mass Effect likely would not have gotten anywhere if BioWare's creative team hadn't been influenced by existing sci-fi stories.
The world of Mass Effect was inspired by various sci-fi stories, films and BioWare's previous games, all bolstered by actual scientific concepts that add a sense of authenticity. Beyond that, the series overall is a fantastic homage and reconstruction of various space opera concepts. Here are some films that had a major influence on Mass Effect's concepts, characters and art design.
Star Wars
More fantastical than the other entries on this list, Star Wars' massive scope allows the story to expand into many different mediums -- including BioWare's own Knights of the Old Republic games, which was itself a massive influence on Mass Effect. There are many key elements to the Mass Effect universe that resemble aspects from Star Wars, particularly the concept of the telekinetic biotic abilities mirroring the Force.
Holographic messages and advanced robotic assistants in Mass Effect are clearly inspired those of Star Wars' droids and hologram projectors. Story-wise, the first game's antagonist Saren Arterius has many similarities with Darth Vader, being super-powered cybernetic lieutenants to a more powerful force who attempt to lure the hero to their side.
Star Trek
Star Trek rivals Star Wars as one of the biggest influences in sci-fi more broadly. Focusing more on interactions between different alien societies and exploring the unknown than on epic interstellar conflicts, Star Trek's stories address social issues and grand moral dilemmas with a sci-fi twist.
Mass Effect's Normandy is similar to the U.S.S. Enterprise in that it's almost a character in and of itself. Similarly to Star Trek, Mass Effect has a heavy focus on exploring alien worlds and the heroes' influence on galactic politics. The designs of aliens in Mass Effect and their relations with humans is also inspired by Star Trek, most notably the blue-skinned, all-female Asari race being based on the green-skinned, matriarchal Orion race.
Stargate
Stargate is unique in its focus on military fiction, with an emphasis on how the U.S. armed forces would handle extraterrestrial activities. The franchise revolves around the eponymous Stargates, ring-shaped devices that act as two-way doors to other worlds, allowing interstellar travel between multiple planets in a short amount of time. Starting with a feature film, Stargate became a household name with the television series SG-1, following a branch of the U.S. Air Force dedicated to stopping alien threats through the Stargate.
Mass Effect's mass relays are important staples of the universe, as well as a clear reference to the Stargates with their ability to make interstellar travel possible. Both Mass Effect and Stargate follow protagonists who are enlisted in the military, dealing with interstellar conflicts as if they were real military operations. Both franchises also take plenty of inspiration from real-world mythology, particularly Greek, Egyptian and Norse tales.
2001: A Space Odyssey
There are a great many sci-fi franchises that owe so much to Stanley Kubrick's masterpiece 2001: A Space Odyssey, and Mass Effect is no exception. The film follows humanity's strange relationship with an ancient alien obelisk as it influences humankind's intellectual and scientific advancement from its prehistoric beginnings to its achievements in space during the year 2001.
So much of 2001's art design and architecture has influenced sci-fi space station design. Mass Effect 3 has a scene where Shepard talks through a structure with no gravity, mirroring Dave walking across the station with no visible gravity in sight. HAL-9000 is also the archetypical rogue AI, influencing characters such as the Geth, EDI and other races' fear of artificial intelligence. The Prothean beacons also mirror the alien obelisk in its transferring of information and advancing technology by centuries.