T4 is a scheduling slot on Channel 4 (UK) from about 9 a.m. until 2.00pm on Saturday and 5.00pm on Sundays. It also airs on weekdays in the school holidays, the "T" nominally standing for teenager. The slot has a separate station identification on screen graphic from Channel 4 and E4. The logo of T4 is noticeably the top right segment of the standard channel 4 logo.

The slot is targeted at the 16-25 age group and the current presenters of T4 include Steve Jones, Anthony Crank, Miquita Oliver, Alex Zane and Alexa Chung. Previous presenters have included Dermot O'Leary, Margherita Taylor, Ben Shephard, June Sarpong and Vernon Kay. The 'voice of T4' is provided by James Delow.

T4 Executives are Richard Cook (Executive Producer) and Jessica Sebastian (Series Producer). It was created by Andi Peters, a former CBBC presenter and Channel 4 commissioning editor for children's and youth at the time.

Early on in T4's run, programmes aimed at children often aired in addition to the content aimed at older viewers, with shows such as CatDog and 2 Stupid Dogs appearing in the early schedule of the strand. Around 2001, this was dropped and the strand refocused entirely towards the teen/youth market. For the first few months of T4's life, its idents consisted of an animated spaceman like character. In 1999, this character instead appeared on the idents during the early morning pre-school shows, in addition to the weekend children's programmes that fell outside the T4 strand. These idents continued in use until 2004.

T4 also stages an annual summer concert, T4 on the Beach, in the resort of Weston-super-Mare. The 2006 concert featured musical acts such as McFly, Razorlight, Will Young and The Zutons. Each act performs two or three songs, but these are generally mimed as the concert is produced for a TV audience. The concert on 22 July 2007 will be the third year running that 'T4 On the Beach' has taken place in Weston-super-Mare.

Also, after E4's launch in 2001, T4 initially also had a slot on the channel. However, this was short lived. They also had an equally short lived Friday evening slot on Channel 4. Following the sale of Quiz Call by Channel 4, it is rumoured that a T4 channel was one of the proposals to fill the vacant slot on Freeview (and subsequently on satellite and cable). However, the plan is also thought to have been rejected by director of television Kevin Lygo, as the slot was filled by Film4+1 (now replaced, in turn, by Channel 4+1).