Netwide Assembler

NASM
Original authorsSimon Tatham, Julian Hall
DevelopersH. Peter Anvin, Chang Seok Bae, Jim Kukunas, Frank B. Kotler, Cyrill Gorcunov
Initial releaseOctober 1996 (1996-10)
Stable release
3.01  / 11 October 2025 (11 October 2025)
Written inAssembly, C
Operating systemUnix-like, Windows, OS/2, MS-DOS
Available inEnglish
Typex86 assembler
LicenseBSD 2-clause
Websitenasm.us
Repository

The Netwide Assembler (NASM) is an assembler and disassembler for the Intel x86 architecture. It can be used to write 16-bit, 32-bit (IA-32) and 64-bit (x86-64) programs. It is considered one of the most popular assemblers for Linux and x86 chips.

It was originally written by Simon Tatham with assistance from Julian Hall. As of 2016, it is maintained by a small team led by H. Peter Anvin. It is open-source software released under the terms of a simplified (2-clause) BSD license.