The 128-bit architecture is a microprocessor or computer architecture that has a datapath width or a highest operand width of 128 bits or 16 octets. These architectures typically have a matching register file with registers width of 64 bits.

There are currently no mainstream microprocessors or systems that operate on general purpose 128-bit integers registers and data addresses, however there are a number of microarchitectures that introduced various extensions to handle 128-bit arithmetic in a more specialized way.