Bad Girls is a British television drama series that was broadcast on ITV from 1 June 1999 until 20 December 2006. It was created by Maureen Chadwick and Ann McManus of Shed Productions, who initiated the idea of developing a series primarily focusing on the inmates and staff of the fictional women's prison, Larkhall, located in the South London region. Following the success of previous series Within These Walls and the Australian-imported Prisoner: Cell Block H, both of which screened on ITV, Bad Girls was commissioned by the network and was viewed as a realistic, modern portrayal of life in a women's prison. The series featured a large ensemble cast, including Linda Henry, Claire King, Simone Lahbib, Mandana Jones, Debra Stephenson, Jack Ellis, Alicya Eyo, Helen Fraser, Kika Mirylees, Victoria Alcock, James Gaddas, Victoria Bush, Dannielle Brent and Liz May Brice.

Unlike past prison series, Bad Girls storylines were portrayed in a more graphic manner in terms of violence, language, and sexual content, as prior shows were somewhat more restrictive in content. Common themes in the series include separation from families, recidivism and adjustment to prison life, while storylines concern the friendships and relationships between the inmates and staff alike, and to a more serious extent, the series focused on sensitive issues such as bullying, rape, suicide, miscarriage, drug use and violence against women, and as a result, was screened past the watershed. It is also notable in that lesbian, gay, bisexual and transgender characters are portrayed in a more permissive way.

The show achieved critical acclaim, becoming immensely successful, particularly throughout the course of its first three years. It constantly attracted high viewing figures, peaking at 9.49 million viewers during the ninth episode of the second series, the highest rated episode of any series produced by Shed Productions. The series began to decline very slightly during its fourth and fifth series' due to an overturn of popular characters, yet the show remained successful in the ratings. However, its popularity began to rise once again with the show's sixth series. This was followed by a rapid decline for the seventh and eighth series', which ultimately led to the show's demise. Due to its success, the series received numerous awards, most notably at the National Television Awards, a crossover with Footballers' Wives, and a musical adapted from the original series, titled Bad Girls: The Musical. Bad Girls gained international success in countries including the United States, Australia, Ireland and several European countries.