The S60 Platform (formerly Series 60 User Interface) was a software platform for smartphones that runs on top of the Symbian operating system. It was created by Nokia based on the 'Pearl' user interface from Symbian Ltd. It was introduced at COMDEX in November 2001 and first shipped with the Nokia 7650 smartphone. The platform has since seen 5 updated editions. Series 60 was renamed to S60 in November 2005.

In 2008, the Symbian Foundation was formed to consolidate all the assets of different Symbian platforms (S60, UIQ, MOAP), making it open source. In 2009, based on the code base of S60, the first iteration of the platform since the creation of Symbian Foundation was launched as S60 5th Edition, or Symbian^1, on top of Symbian OS 9.4 as its base. Subsequent iterations were named Symbian^2 (Japanese market only) and Symbian^3.

The S60 software was a multivendor standard for smartphones that supports application development in Java MIDP, C++, Python and Adobe Flash. Its API was called Avkon UI. S60 consists of a suite of libraries and standard applications, such as telephony, personal information manager (PIM) tools, and Helix-based multimedia players. It was intended to power fully featured modern phones with large colour screens, which are commonly known as smartphones.

Originally, the most distinguishing feature of S60 phones was that they allowed users to install new applications after purchase. Unlike a standard desktop platform, however, the built-in apps are rarely upgraded by the vendor beyond bug fixes. New features are only added to phones while they are being developed rather than after public release. Certain buttons are standardized, such as a menu key, a four way joystick or d-pad, left and right soft keys and a clear key.

S60 was mainly used by Nokia but they also licensed it to a few other manufacturers, including Lenovo, LG Electronics, Panasonic, Samsung, Sendo, Siemens Mobile, Sony Ericsson, Solstice and Vertu. Sony Ericsson notably was the main vendor using the competing UIQ Symbian interface.

In addition to the manufacturers the community includes:

• Software integration companies such as Sasken, Elektrobit, Teleca, Digia, Mobica, Atelier.tm
• Semiconductor companies Texas Instruments, STMicroelectronics, Broadcom, Sony, Freescale Semiconductor, Samsung Electronics
• Operators such as Vodafone and Orange who develop and provide S60-based mobile applications and services
• Software developers and independent software vendors (ISVs).