ST-Ericsson is a global wireless platform and semiconductor supplier to four of the top five mobile handset manufacturers. ST-Ericsson is a 50/50 joint venture of Ericsson and STMicroelectronics established on February 3, 2009. Headquartered in Geneva, Switzerland, it is a fabless company, meaning that it does not do the actual manufacturing of semiconductors.

ST-Ericsson was formed on February 3, 2009 when STMicroelectronics and Ericsson completed the merger of Ericsson Mobile Platforms and ST-NXP Wireless into a 50/50 joint venture.

On August 20, 2008, STMicroelectronics and Ericsson announced their intention to merge their wireless semiconductor businesses with the goal of creating the industry's strongest product offering in semiconductors and platforms for mobile applications. ST contributed its multimedia and connectivity solutions as well as a complete 2G/EDGE platform and 3G offering. Ericsson contributed its 3G and 3GPP Long Term Evolution (LTE) platform technology. The merger, which built on an existing strategic co-operation between Ericsson Mobile Platforms and ST-NXP Wireless, was also designed to generate significant scale and synergies.