OnStar Corporation is a subsidiary of General Motors that provides subscription-based communications, in-vehicle security, emergency services, hands-free calling, turn-by-turn navigation, and remote diagnosticssystems throughout the United States, Canada, China, Mexico, Europe, Brazil, and Argentina. A similar service is known as Opel OnStar in western Europe and ChevyStar in Latin American markets (except in Mexico, Brazil and Argentina). In September 2011 the president of OnStar stated that the service had more than six million customers. On 9 May 2018, Vauxhall Motors announced that Vauxhall OnStar, alongside Opel OnStar services, will cease to operate after December 31, 2020, following Vauxhall Motors and Opel being purchased from General Motors by Groupe PSA. Onstar unit in a 2008 Chevrolet Impala

A new aftermarket interior rear-view mirror with a built-in OnStar module, branded as OnStar FMV, became publicly available on July 24, 2011. It provides some of the features an OEM system has, such as Automatic Crash Response, Stolen Vehicle Tracking, Turn-by-Turn Navigation, and Roadside Assistance.