Blaenau Gwent and Rhymney () is a constituency of the House of Commons in the UK Parliament, first contested at the 2024 general election, following the 2023 review of Westminster constituencies. It is currently represented by Nick Smith of the Labour Party, who was the MP for the predecessor constituency of Blaenau Gwent from 2010 to 2024.
Under the 2023 review, the constituency was defined as being composed of the following, as they existed on 1 December 2020:
Following local government boundary reviews which came into effect in May 2022, the constituency now comprises the following from the 2024 general election:
It comprises the whole of the abolished Blaenau Gwent constituency, which was coterminous with the county borough of the same name, together with the Rhymney valley which was previously part of the abolished Merthyr Tydfil and Rhymney constituency. Small areas also transferred from Caerphilly and Islwyn (abolished).
Stewart Sutherland was nominated as the Reform UK candidate, but withdrew prior to the close of nominations due to reposting racist content on social media.