Big Brother 2017, also known as Big Brother 18 and The United Kingdom of Big Brother, was the eighteenth series of the British reality television series Big Brother, hosted by Emma Willis and narrated by Marcus Bentley. The series launched on 5 June 2017 on Channel 5, and ended after 54 days on 28 July 2017. Rylan Clark-Neal continues to present the spin-off show Big Brother's Bit on the Side. The series, along with its spin-off, continues to air on 3e in Ireland, as part of a three-year deal between the Irish broadcaster and Endemol Shine Group. It is the seventh regular series and the nineteenth series of Big Brother in total to air on Channel 5 to date.
On Day 7, Arthur Fulford left the house for unexplained reasons.Sukhvinder Javeed also became the first housemate to voluntarily walk from the house through the front door during her husband Imran's eviction on Day 12.Kayleigh Morris and Lotan Carter were also removed from the house on Day 13 and Day 21, respectively, for aggressive behaviour and threatening physical violence.
On 28 July 2017, Isabelle Warburton was announced as the winner of the series having receieved 52.71% of the final vote, with Raph Korine as the runner-up after receiving 22.02%. Isabelle is the second late entrant after Brian Belo, and the first female late entrant to win Big Brother.