IA-32 (Intel Architecture, 32-bit), also known as x86-32, i386 or x86, is the CISCinstruction-set architecture of Intel's most commercially successful microprocessors, and was first implemented in the Intel 80386 as a 32-bit extension of x86 architecture. This architecture has defined the instruction set for the family of microprocessors currently installed in most personal computers in the world, although it is now being supplanted by x86-64.

The IA-32 instruction set was introduced in the Intel 80386 microprocessor in 1986 and remains the basis of most PC microprocessors over twenty years later. Even though the instruction set has remained intact, the successive generations of microprocessors that run it have become much faster. Within various programming language directives, IA-32 is still sometimes referred to as the "i386" architecture.

Intel Corporation is the inventor and the biggest supplier of IA-32 processors. The second biggest supplier is AMD. As of 2011^[update], both Intel and AMD have moved to x86-64, but still produce IA-32 processors such as Intel Atom (N2xx and Z5xx series) and Geode. VIA Technologies continues to produce the VIA C3/VIA C7 family of "pure" IA-32 devices. For a time, Transmeta produced IA-32 processors.