A woman was groped from behind while on the dance floor at Rock City.
Police are trying to trace the man responsible after the incident on November 28 last year.
Police have released an image of a man they wish to speak to in connection with the sexual offence.
The incident happened at around 10pm at the venue.
A spokesman for Nottinghamshire Police said: "Do you recognise this man?
"Officers would like to speak to this man in connection with a sexual offence.
"The incident happened at around 10pm on 28 November 2019 in Rock City in Nottingham.
"A woman was groped from behind whilst on the dance floor.
"If you recognise him please call us on 101, quoting incident number 19 641830."
