Red vs. Blue, often abbreviated as RvB, is a set of related machinima comic science fiction video series created by Rooster Teeth Productions and distributed primarily through the Internet and DVD. The story centers on two opposing teams of soldiers fighting a civil war in the middle of a desolate box canyon (Blood Gulch), in a parody of first-person shooter (FPS) games, military life, and science fiction films. Initially intended to be a short series of six to eight episodes, the project quickly and unexpectedly achieved significant popularity following its Internet premiere on April 1, 2003. Rooster Teeth therefore decided to continue the story. The fifth and final season of the original Red: vs. Blue: The Blood Gulch Chronicles series ended with episode 100, released on June 28, 2007. Three mini-seriesOut of Mind, Recovery One, and Relocatedand the full-length Reconstruction series have extended the plot.

Red vs. Blue emerged from Burnie Burns’ voice-over-enhanced gameplay videos of Bungie Studios’ FPS video game Halo: Combat Evolved. The series is primarily produced using the machinima technique of synchronizing video footage from a game to pre-recorded dialogue and other audio. Footage is mostly from the multiplayer modes of Halo: Combat Evolved and its sequels, Halo 2 and Halo 3, on the Microsoft Xbox and Xbox 360 video game consoles.

Both within the machinima community and among film critics, Red vs. Blue has been generally well-received. Praised for its originality, the series has won four awards at film festivals held by the Academy of Machinima Arts & Sciences. It has been credited with bringing new popularity to machinima, helping it to gain more mainstream exposure, and attracting more people to the art form. Graham Leggat, former director of communications for Lincoln Center’s film society, described Red vs. Blue as "truly as sophisticated as Samuel Beckett."[1] While special videos continue to be released online, the completed series is also available on DVD, making the series one of the first commercially released and successful machinima products. Rooster Teeth has created videos, some under commission from Microsoft, for special events, and Red vs. Blue content is included with the Legendary Edition of Halo 3.