libjpeg-turbo is a derivative of libjpeg which uses SIMD instructions (MMX, SSE2, etc.) to accelerate baseline JPEG compression and decompression on x86 and x86-64 systems.  On such systems, libjpeg-turbo is generally 2-4x as fast as the unmodified version of libjpeg, all else being equal.  libjpeg-turbo also includes a wrapper library which implements the TurboJPEG API used by VirtualGL and TurboVNC.

libjpeg-turbo was originally based on libjpeg/SIMD by Miyasaka Masaru, but the TigerVNC and VirtualGL projects made numerous enhancements to the codec in 2009, including improved support for Mac OS X, 64-bit support, support for 32-bit and big endian pixel formats (RGBX, XBGR, etc.), accelerated Huffman encoding/decoding, and various bug fixes.  The goal was to produce a fully open source codec that could replace the partially closed source TurboJPEG/IPP codec used by VirtualGL and TurboVNC.  libjpeg-turbo generally performs in the range of 80-120% of TurboJPEG/IPP.  It is faster in some areas but slower in others.

In early 2010, libjpeg-turbo spun off into its own independent project, with the goal of making high-speed JPEG compression/decompression technology available to a broader range of users and developers.