Tim "Tinhead" O'Leary is a fictional character from the British Channel 4 soap opera's Brookside and Hollyoaks, played by Philip Olivier. The character debuted on-screen during the episode broadcast on 22 May 1996. Tim remained on-screen until the final episode of the series in 2003. Tim subsequently appeared in a video spin-off, Brookside: Unfinished Business. Olivier returned as Tim in a 2025 Brookside and Hollyoaks crossover episode as part of latter series’ thirtieth Anniversary. Olivier continued to appear in the role during Hollyoaks episodes broadcast in January 2026 when the show had him enter into a relationship with Liberty Savage (Jessamy Stoddart) as well as having links to gangster character Warren Fox (Jamie Lomas).

In his early years, Tim was portrayed as a "bad lad" and school bully. Tim dislikes Danny Simpson (Andrew Butler) because he is a snob and bullies him. He forms a friendship with Leo Johnson (Steven Cole) but becomes a bad influence on him. Tim begins to commit petty crimes such as breaking into the Simpson's house and stealing a computer. He then hides a load of stolen alcopops at the local youth group. Jimmy Corkhill (Dean Sullivan) identifies Tim as the culprit but decides to help him avoid being caught by the police. Tim's bad behaviour eventually leads to his expulsion from school, despite his mother works at the local school as a governor. Writers continued to use Jimmy in transforming Tim's character and he is portrayed investing more time trying to correct Tim's wayward behaviour. He offers Tim work delivering pizzas but is shocked to discover he has been overcharging customers for their meal. Jimmy's wife Jackie Corkhill (Sue Jenkins) tries to discourage him from helping Tim anymore. Jimmy ignores her wishes because he does not want Tim to end up like his son Little Jimmy Corkhill (George Christopher).

A writer from the show's official website described Tim as being "the cause of much consternation" for his neighbours "as he stomped around with unchecked bravado." It was "inevitable" that Tim's "outlandish behaviour" got him into trouble with the law. However, writers used Sinbad Sweeney as a father figure for Tim and with his guidance Tim became "more settled and mature". Writers later paired Tim with Emily Shadwick (Jennifer Ellison), who led Tim back into his old ways. Tim's "resistance to Emily's feminine wiles is practically non existent". His involvement with Emily ultimately ends up with Tim being sent to prison. In 2002, Olivier stated "it's fun playing a bad lad". He added that he was nothing like his character because "Tim is a lot more daring and jumps before he thinks."

Olivier also played the role in a direct to DVD spin-off, titled Brookside: Unfinished Business. The spin-off was released following Brookside's finale and focuses on Tim and Steve's rivalry with Terry Gibson (Greg Milburn). In the story, Terry lures Tim and Steve to a woodland hideaway for a violent showdown.

On 1 September 2025, it was announced that Olivier had reprised her role for a Brookside and Hollyoaks crossover episode as part of latter's 30th Anniversary. Of his return, Olivier stated that it was "a delight and surprise" to be asked to reprise the role and would "relish returning" to Brookside Close. He added that he would not have believed at aged fifteen, when he joined the cast, that people would still call him "Tinhead" thirty years later. The episode was broadcast on 22 October 2025 and featured Tim on-screen with his old neighbours, Nikki Shadwick (Suzanne Collins) and Sinbad (Michael Starke). Olivier reprised the role again and Tim returned to Hollyoaks in January 2026. His return was announced alongside Suzanne Collins and Starke, who play Nikki and Sinbad respectively. Writers paired Tim in a new relationship storyline with the established Hollyoaks character, Liberty Savage (Jessamy Stoddart). Though it was revealed that Tim would have an "ulterior motive" for being in Chester.

"Tinhead" made his first appearance in Brookside as a school bully at Brookside Comprehensive in 1996. Danny Simpson (Andrew Butler) was Tinhead's main target, as he tried to bully him into helping him with his schoolwork. Tinhead was the leader of a gang of boys who continued to terrorise other pupils despite protests made to the head teacher by their parents. Later Danny gave Tinhead some schoolwork, knowing that he was going to take the credit for it, but Danny deliberately made the project complete nonsense so Tinhead was made to look a fool in front of his classmates. Tinhead decided to teach Danny a lesson, so after school he chased Danny and his mate Leo intending to give Danny a good beating, but when he escaped it was Leo who was left battered and bruised. Leo tried later to become part of Tinhead's gang by helping him steal a computer from the Simpsons' house on Brookside Close. Mick (Louis Emerick), Leo's father, tried to get Tinhead expelled from school for bullying, but came across an unexpected problem when he discovered that Tinhead's mother Carmel O'Leary (Carol Connor) was one of the school governors. Carmel refused to believe that her son was the ring leader of the gang of bullies.

Sinbad later became involved in a relationship with Carmel and did his best to help her to try to get Tinhead to change his ways. Tinhead had other ideas, and took every opportunity to try and cause trouble between them. Jimmy also had a run in with Tinhead when he discovered that he was responsible for bringing alcohol into the youth club .

As tension in the O'Leary house continued to mount with Tinhead and Sinbad still at loggerheads, Tinhead left home having decided to squat in the flat above Mick Johnson's Pizza Parlor. While there, he thought he could make some easy money by selling the washing machine that was in the flat. Tinhead's plan backfired when he tried to remove the machine without turning off the water supply which resulted in him flooding the flat and causing extensive damage to Mick's shop below. Both Mick and Sinbad suspected that Tinhead was involved, but Carmel refused to believe he was the culprit. In an effort to make Tinhead a more responsible person Sinbad convinced David Crosbie (John Burgess) to give him a job at the petrol station, but it's not long before Tinhead, who resented being made to work, caused trouble when he put diesel in Ron Dixon (Vince Earl)'s petrol car.