3GP Timed Text (TTXT) is a text-based subtitle format defined by the 3rd Generation Partnership Project (3GPP). It is used within 3GP multimedia files, primarily for mobile phones.

3GP Timed Text was introduced to standardize the presentation of text within the 3GP multimedia container format, primarily used for mobile phones. The format is detailed in the 3GPP TS 26.245 specification and was designed to support efficient and synchronized text rendering alongside audio and video streams in 3G mobile multimedia services. This functionality was crucial for enabling features such as subtitles and captions on mobile devices with limited processing power and storage. The format became a model for the MPEG-4 Part 17 (MPEG-4 Timed Text) standard, which is also used for streaming text in multimedia applications.