Melanie Onn (born 19 June 1979) is a British Labour Party politician who was elected as the Member of Parliament (MP) for Great Grimsby in May 2015 until the dissolution of parliament in November 2019.
She previously served as Shadow Deputy Leader of the House of Commons from September 2015 to June 2016 and Shadow Minister for Housing from July 2017 to March 2019.
At the 2019 general election, she lost her seat to the Conservative candidate Lia Nici-Townend.