RapidIO is a packet-switched interconnect technology used to link electronic components. It allows devices to exchange messages, perform read and write operations, and maintain cache coherence. RapidIO follows common electrical standards, such as those used in Ethernet, and can connect chips, circuit boards, or entire systems together.

The RapidIO Trade Association was founded around February 2000 with early members such as Cisco Systems, Galileo Technology, HAL Computer Systems, Lucent Technologies, Mercury Computer Systems, Motorola, Nortel Networks, Seagull Semiconductor, Tundra Semiconductor, and Xilinx. The RapidIO protocol was originally designed by Mercury Computer Systems and Motorola (Freescale) as a replacement for Mercury's RACEway proprietary bus and Freescale's PowerPC bus.

The RapidIO specification revision 1.1 (3×N Gen 1), released in March 2001, defined a wide, parallel bus. This version did not achieve broad commercial deployment.

The RapidIO specification revision 1.2, released in June 2002, defined a serial interconnection based on the XAUI physical layer. Devices based on this specification saw commercial use in wireless baseband, imaging and military computing.

The RapidIO specification revision 1.3 was released in June 2005.

The RapidIO specification revision 2.0 (6xN Gen2), was released in March 2008. This added more port widths (2×, 8×, and 16×) and increased the maximum lane speed to 6.25 GBd / 5 Gbit/s.

The RapidIO specification revision 2.1 was released in September 2009.

The RapidIO specification revision 2.2 was released in May 2011.