4oD is a video on demand service from Channel Four Television Corporation. Launched in November 2006, 4oD stands for "4 on Demand". The service offers a variety of programmes recently shown on Channel 4, E4, More4 or from their archives. However some programmes and movies are not available due to rights issues.

The cable and IPTV versions are operated through an appropriate set-top box whilst the internet variant can be accessed via websites such as Channel4.com. 4oD generated around 215 million long-form video views on all platforms where it is available in the first half of 2011, making Channel 4 the biggest UK broadcaster in the video on-demand market during the period.

4oD is the main source of on demand programmes from Channel 4, E4 and More4, the catch up service currently lasts 30 days and the archive has thousands of hours of programming.

As of April 2009, the internet version is fully available to Windows, Mac and Linux users with Adobe Flash Player installed.

The "catch-up" service offers content free of charge a programme for thirty days after its broadcast on Channel 4. At this time,^[when?] not all content is available to Irish users, due to licensing restrictions, however the majority of the programming is available.