The Small Form Factor Special Interest Group (SFF-SIG, pronounced ess-eff-eff-sig) is an international non-profit standards body focused on modular computer hardware technologies used in embedded and small form factor computers and controllers.

Members use the specifications to build specialized embedded computers used in both commercial and rugged environments where applications insist on reliable control and data acquisition, for example.

Primarily focused on hardware, SFF-SIG defined new single-board computer (SBC) and computer-on-module (COM) form factors.

SFF-SIG standardizes expansion connectors to create the building blocks required by system manufacturers.

Specifications often use pre-existing interface buses and interconnects such as PCI Express, USB 2.0,[4] ExpressCard,[5] Low Pin Count (LPC) Bus,[6] SPI / uWire,[7] and I2C / SMBus,[8] with adaptations for modular and extensible usage.