Pixar RenderMan is a photorealistic 3D rendering software produced by Pixar Animation Studios. Pixar uses RenderMan to render their in-house 3D animated movie productions and it is also available as a commercial product licensed to third parties. In 2015, a free non-commercial version of RenderMan became available.

To speed up rendering, Pixar engineers performed experiments with parallel rendering computers using Transputer chips inside a Pixar Image Computer. The name comes from the nickname of a small circuit board (2.5 × 5 inches or 6.4 × 13 cm) containing one Transputer that engineer Jeff Mock could put in his pocket. During that time the Sony Walkman was very popular and Jeff Mock called his portable board Renderman, leading to the software name.

RenderMan defines cameras, geometry, materials, and lights using the RenderMan Interface Specification. This specification facilitates communication between 3D modeling and animation applications and the render engine that generates the final high-quality (HQ) images. In the past, RenderMan used the Reyes Rendering Architecture. The Renderman standard was first presented at 1993 SIGGRAPH, developed with input from 19 companies and 6 or 7 big partners, with Pat Hanrahan taking a leading role. Ed Catmull said no software product met the RenderMan Standard in 1993. RenderMan met it after about two years.

Additionally RenderMan supports Open Shading Language to define textural patterns.

When Pixar started development, Steve Jobs described the original goal for RenderMan in 1991:

"Our goal is to make Renderman and Iceman the system software of the 90s," Mr. Jobs said, likening these programs to PostScript, the software developed by Adobe Systems Inc. for high-quality typography.

— Lawrence M. Fisher,

During this time, Pixar used the C language for developing Renderman, which allowed them to port it to many platforms.