ITV3 is an entertainment television channel in the United Kingdom owned by ITV plc which shows mainly older drama shows. In some regards, it is the continuation of older channel Granada Plus.

It launched on the terrestrial (Freeview), cable (NTL and Telewest) and digital satellite (Sky Digital) on 1 November 2004 at 9.00pm.

The channel had been available from launch on NTL Ireland, but was pulled on 22 March 2006. This is believed to have been at the request of ITV plc, which had previously barred Irish newspapers from publishing details of ITV channels and regions other than UTV and Men & Motors.

The channel is mainly aimed at the over 35 audience, and the company are hoping to use it, and extra investment into its ITV2 channel to triple non-terrestrial revenue within five years. ITV's attempt to secure more ratings for the channel has led to the network purchasing the exclusive terrestrial television rights to a number of newer and in some cases popular US drama series, such as NUMB3RS and more recently Law & Order: Trial by Jury.

Originally speculation was rife over whether it would launch on the Digital Satellite platform immediately, but after a deal whereby the transmission of a very similar ITV controlled channel, Plus, was hastily ceased just 30 minutes prior to launch, ITV3 took its channel number and bandwidth meaning all platforms could launch simultaneously. Staff at Plus were given 15 minutes' notice. On satellite, it is available as a free-to-air channel, and as such does not require an active Sky Digital subscription.

ITV launched a one hour timeshift channel of ITV3 on Monday, 30 October 2006. ITV2+1 launched on the same day. This channel is often unable to broadcast certain programmes "for legal reasons", but the programme in question might still be listed on the EPG.

During the 2007 Rugby World Cup, ITV3 broadcat some of the matches while ITV1 and ITV4 were showing live European football matches which were being played at the same time.