Rich Text Format (RTF) is a file format that was developed and standardized by Microsoft Corporation for creating formatted text files. The RTF format is all-purpose and widespread. Almost every word processing program in different operating systems can open, create or edit RTF formatted documents. For this reason, it is often used to transfer formatted text files among several different computer systems using different word processing programs.

More than a basic text file, the RTF format also contains formatting features, such as text style, size, colour, tables, different fonts and so on. The formatting features are specified by an internal mark-up language. However, RTF does not support all features of a full word processor, like Microsoft Word.

As Microsoft Word and MS Office are improved continuously and their new versions have been published periodically, the RTF specification has also been revised several times. The first version of the specification was published in 1987. The latest version is 1.9.1 published in 2008.