The programme was created by Will Brenton and Iain Lauchlan, a pair with a track record of being involved in BBC children's programming.Iain Lauchlan was a presenter on Play School, Fingermouse and Playdays, meeting Brenton, a director, writer and also a presenter, during the latter. Together they started producing two of the Playdays strands before forming their own production companies Tell-Tale Productions and, more recently, Wish Films. They also created The Fun Song Factory, Boo!, BB3B!, Jim Jam and Sunny, Basil Hair The Squirrel and Entertainment Right's The Magical Lives of Toys.
Tweenies is a production of Tell-Tale Productions in association with the BBC. Animation for the show was produced by A Productions, an animation studio based in Bristol, England, with Ealing Animation providing some animation in a few early episodes. Computer animation for the series was provided by Clockwork Digital, with Ben Mars animating Mungo, the computer creature who appears in some later episodes.
The programme is set in a nursery attended by the four Tweenies themselves: Milo, Jake, Bella and Fizz. They are supplemented by two adults, Max and Judy, and two dogs, Doodles and Izzles.
The show includes a "Tweenie Clock", with five circular lights arranged in a pentagonal shape with the lights denoting "news time", "messy time", "song time", "telly time" and "story time". "Surprise time" is a special time determined when all five lights glow. A button at the centre of the clock is pressed to select the activity that will be undertaken next.