Melanie Onn (born 19 June 1979) is a British politician who has been Member of Parliament (MP) for Great Grimsby and Cleethorpes since 2024.

[3][4][5] At the age of 17, after falling out with her aunt, with whom she had been living, Onn sought help from Doorstep, a Grimsby-based charity which provides housing support to young people.

[10] Onn was selected as the Labour candidate for Great Grimsby from an all-women shortlist in July 2014, following the announcement that the sitting MP, Austin Mitchell, would retire at the next election.

[17] At the final third reading, Onn voted against the Welfare Reform and Work Bill along with all Labour MPs.

[19] Onn campaigned for Britain to remain in the European Union, despite her constituency voting to leave by one of the largest margins in the country.

[24] She supported Owen Smith in the failed attempt to replace Corbyn in the 2016 Labour leadership election.

[25] On 7 September 2016, Onn introduced a private members' bill to protect workers' rights in British law after Brexit.

The bill was scheduled for its second reading in the House of Commons on 13 January 2017, but was successfully filibustered by Conservative members of Parliament.

[28] During a Westminster Hall debate that she led in March 2018, Onn proposed that misogyny should be treated as hate crime.

[32] Onn is a campaigner to change the law to give greater protection to alleged rape victims.