William Sanford Nye —a.k.a. Bill Nye the Science Guy— (born November 27, 1955, Washington, D.C.), is a science educator and comedian who began his career as an engineer at Boeing. He is best known as the host of the Disney/PBS children's science show Bill Nye the Science Guy (1993–98) and for his many subsequent appearances in popular media as a science presenter. When portraying "The Science Guy", he wears a light blue lab coat and a bow tie, and takes on the persona of an excited, jocular science educator. Nye is a graduate of Cornell University with a Bachelors of Science degree in Mechanical Engineering. Among other things, he developed a hydraulic pressure resonance suppressor still used in the 747 and fitted the Mars rovers with photometric calibration Mars Dials.
Professor Proton contacts Leonard to ask to read a paper he wrote. Sheldon, who has loved Professor Proton since childhood, seeks revenge by deceiving Bill Nye to get him to Caltech.  In the end, Sheldon has a new person who takes out a restraining order against him.He reappeared in "The Conjugal Configuration" when a combative Neil deGrasse Tyson makes a prank phone call to him.
- His counterpart, Professor Proton, is also a graduate of Cornell University.
- Carl Sagan was one of Bill Nye's professors at Cornell. Sheldon has a restraining order from Sagan. ("The Vacation Solution")
- Sheldon would later receive a restraining order from Nye himself ("The Proton Displacement").
- He appeared alongside Neil deGrasse Tyson in an episode of Stargate Atlantis. Dr. Tyson made a cameo in "The Apology Insufficiency", while Sheldon referenced "Stargate" in "The Cushion Saturation".
- Penny knows him as "Creepy Old Guy from Dancing with the Stars".
- Bill Nye is acquainted with Buzz Aldrin, who had a cameo in "The Holographic Excitation".
- Bill Nye is the first member of a Back to the Future related production to appear in The Big Bang Theory. His role was being the lab assistant to Doctor Emmett Brown (played by Christopher Lloyd who later appeared in "The Property Division Collision") in the Video encyclopedia segments of Back to the Future: The Animated Series.