iOS (formerly iPhone OS)[6] is a mobile operating system developed by Apple exclusively for its mobile devices. It was unveiled in January 2007 for the first-generation iPhone,[7] which launched in June 2007. Major versions of iOS are released annually; the current stable version, iOS 18, was released to the public on September 16, 2024.[8]

Besides powering iPhone, iOS is the basis for three other operating systems made by Apple: iPadOS, tvOS, and watchOS.[9] iOS formerly also powered iPads until iPadOS was introduced in 2019 and the iPod Touch line of devices until its discontinuation.