Shane Patrick Mahan (born September 22, 1964) is an American special effects creator, creature designer, puppeteer, and producer known for his work at Stan Winston Studio and its successor, Legacy Effects. His film credits include The Terminator and Terminator 2: Judgement Day; Aliens; Predator and Predator 2; The Lost World: Jurassic Park; Iron Man, Iron Man 2 and Iron Man 3; Pacific Rim and The Shape of Water.

Mahan was born and raised in Greenville, Michigan. After graduating from Greenville High School in 1981, he left for Hollywood. His first job was with Stan Winston Studios as a crew member working on The Terminator in 1983. There he worked as a creature effects supervisor. After Stan Winston's passing, he formed Legacy Effects with three partners who were also his former colleagues at Stan Winston Studios, and this has now become the leading VFX company in Hollywood.

Mahan and his design team made the special suits worn by Robert Downey Jr. in the film Iron Man. They also designed the suit for Iron Man, which was ten feet tall, weighed 800 lbs, and required five operators to puppeteer. Besides several other nominations, Mahan and his team were nominated for the 2008 Oscar for 'Best Achievement in Visual Effects' for Iron Man. The team was hired as concept artists by James Cameron for his film Avatar. This was special for Mahan, as his first special effects credits were for the film The Terminator.

Mahan worked for Stan Winston Studios until the death of Stan Winston in 2008, when he and three other veterans of the company, Lindsay MacGowan, J. Alan Scott, and John Rosengrant, incorporated Legacy Effects, a character design, make-up, and animatronic studio so named in honour of the late Winston's legacy and lifelong achievements. He lives in Los Angeles.