Libby Fox (initially known as "Squiggle") is a fictional character from the BBC soap opera EastEnders, played by Belinda Owusu. She made her first appearance on 22 May 2006 and left in 2010. She is the daughter of Denise Fox (Diane Parish) and Owen Turner (Lee Ross), and half-sister of Chelsea Fox (Tiana Benjamin). The Fox family were introduced by executive producer Kate Harwood. The character of Libby was featured in a prominent storyline in 2006, when Owen attempts to murder her. The character then cultivates a relationship with her peer Darren Miller (Charlie G. Hawkins). She is portrayed as intelligent and competitive. The character was axed in April 2010 and her departure episode was broadcast on 5 August 2010, when the character departs to study at Oxford University. Libby returned in April 2014 as part of the beginning of the "Who Killed Lucy Beale?" storyline. Since then she continued to make various guest appearances up until 31 January 2017.

Early in Spring 2006, an official BBC press report announced the introduction of a new, all female family joining EastEnders, Denise Fox (Diane Parish) and her two daughters Chelsea (Tiana Benjamin) and Libby (nicknamed Squiggle), cast to Belinda Owusu, who was 16 at the time. Benjamin has revealed that she was the second Fox to be cast, and on her final audition, she had a workshop and met Diane Parish there. Owusu was cast at a later date. Tiana Benjamin who plays Chelsea has said that the three actors who play the Fox family have a bond, commenting "We all respect and understand each other, and manage to have a good time while we're filming too. I felt that we clicked from our first few scenes together."

Described as "the feisty Fox family", the characters first appeared on-screen in May 2006. An insider reportedly said to the Sunday Mirror, "They'll arrive in Albert Square with a bang and they'll cause friction from the off. The Fox girls don't take any nonsense -they'll be a force to be reckoned with." The newspaper described the character of Libby as a superbrat and teenage troublemaker. Owusu commented, "Squiggle is going to cause lots of mischief."

In April 2010 it was announced that the character had been axed along with five others by the new executive producer Bryan Kirkwood. Speaking of her departure, Owusu said: "I've had a great time playing Libby but I agree with Bryan that after four years of great storylines, it is now time for Libby to move on. EastEnders was my first real job and I have learnt so much but I am now really looking forward to trying new roles." Her final episode was broadcast on 5 August 2010.

In March 2014, it was announced that Owusu had agreed to reprise the role of Libby Fox for number of episodes from April 2014, as part of the "Who Killed Lucy Beale?" storyline. She made her on-screen return on 18 April 2014. It was again announced in July 2015 that Libby would return again for a two episode guest stint. Speaking of her return, Owusu said: "It's great to be back again! I'm always excited to see how Libby has grown and be back with the Fox family!" Libby appeared on 3 and 4 August 2015. Libby has since returned over various guest stints: on 11 December 2015, four episodes from 7 to 10 March 2016, four episodes from 22 to 27 April 2016, five episodes from 7 to 17 November 2016 and for a guest stint from 23 December 2016 to 31 January 2017.

Libby is Denise Fox's (Diane Parish) youngest daughter. Libby secretly contacts her estranged father, Owen Turner (Lee Ross), an abusive alcoholic, and he starts making demands to see her. Denise is reluctant to allow this, but Owen seems to have changed, and Libby is keen for her parents to get back together; Denise is swayed and sleeps with Owen. However, as soon as Owen begins drinking again, he becomes abusive and hits her. He is arrested, but Libby persuades Denise to give a glowing character witness statement and he is released. Owen kidnaps Libby and takes her to Epping Forest. He drugs her and tries to kill her and himself by filling the car with noxious exhaust fumes. She escapes, but he catches her and tries to drown her in a stream. Denise arrives to find Libby unconscious on the bank. She is taken to hospital and makes a full recovery. Owen is imprisoned for 5 years.

Libby gets involved in various scams with her friend Darren Miller (Charlie G. Hawkins). She develops a crush on Gus Smith (Mohammed George), but is too young to be noticed by him, so she begins using an internet chat room, talking to a stranger named "Einstein27". She refuses to listen to Yolande Trueman's (Angela Wynter) concerns about the dangers of meeting someone online and agrees to meet him in person. When she meets the stranger, she discovers that she was chatting to Darren all along. He admits to liking Libby. She is initially unimpressed, but after Yolande arranges a meal between them, they decide to start a relationship. A few weeks later Darren visits his family in the Cotswolds, and Libby is heartbroken to discover he has decided not to return. She concentrates on her school work and achieves eleven good GCSE grades.

Darren returns some weeks later but Libby avoids him. When she finally plucks up the courage to see him, she hears him talking about someone called Clara. Thinking he has found someone new, she pretends she is going out with Tamwar Masood (Himesh Patel). It turns out Clara is a dog and the pair get back together. Libby and Darren have an anniversary dinner to celebrate a year of dating. However, Jay Brown (Jamie Borthwick) reveals that Darren frequently looks at pornography. Libby becomes furious and confides in Tamwar with whom she is in the process of starting a home tutoring business. Darren becomes jealous, but eventually reconciles with Libby and begins thinking about starting a sexual relationship with Libby. He invites her round to do this, however Jay ruins the night by telling Libby that Darren told him that she was a virgin. Libby is devastated, but she eventually comes round and she and Darren decide not to rush things.