The GNU toolchain is a broad collection of programming tools produced by the GNU Project. These tools form a toolchain (a suite of tools used in a serial manner) used for developing software applications and operating systems.

The GNU toolchain plays a vital role in development of Linux, some BSD systems, and software for embedded systems. Parts of the GNU toolchain are also directly used with or ported to other platforms such as Solaris, macOS, Microsoft Windows (via Cygwin and MinGW/MSYS), Sony PlayStation Portable (used by PSP modding scene)^[1] and Sony PlayStation 3.^[2]

Projects included in the GNU toolchain are:

• GNU Autotools (GNU Build System): Autoconf, Automake and Libtool
• GNU Binutils: a suite of tools including linker, assembler and other tools
• GNU Bison: a parser generator, often used with the Flex lexical analyser
• GNU C Library (glibc): core C library including headers, libraries, and dynamic loader
• GNU Compiler Collection (GCC): a suite of compilers for several programming languages
• GNU Debugger (GDB): a code debugging tool
• GNU make: an automation tool for compilation and build
• GNU m4: an m4 macro processor

• GNU Classpath
• GNU Core Utilities
• CVS and Git
• MinGW and Cygwin
• Cross compiler
• LLVM