Leigh is a constituency^{[n 1]} in Greater Manchester represented in the House of Commons of the UK Parliament since 2019 by James Grundy of the Conservative Party.

Before this, the seat was represented by Andy Burnham of the Labour Party, who served as the MP from 2001, and Shadow Home Secretary in Jeremy Corbyn's Shadow Cabinet until October 2016.^{[n 2]} Burnham stood down following his victory at the 2017 Greater Manchester mayoral election, and was succeeded by the Labour and Cooperative Party's Jo Platt who was MP from 2017 to 2019. Burnham, who was re-elected as Mayor of Greater Manchester in 2021 with an increased majority, still resides in the Leigh constituency.

As a result of adding the town of Atherton to the constituency, the 2023 Periodic Review of Westminster constituencies proposes that it is renamed Leigh and Atherton, to be first contested at the next general election.^[2]

Leigh is a marginal seat in the south of the Metropolitan Borough of Wigan and on the border with Warrington, with virtually all wards held by the Labour Party at local level, although it does contain the more Conservative-inclined area of Lowton East. In line with the wider borough of Wigan it voted by a majority to Leave the European Union in the 2016 referendum, but has slightly lower levels of deprivation than the town of Wigan itself,^[3] and is mostly made of skilled working-class families in residential areas, with some light industry, all factors in the swing towards the Conservatives in 2019. Leigh, Tyldesley and Golborne are former mill and mining towns undergoing urban regeneration. Pennington Flash in between Lowton and Leigh is an important local nature reserve and area of natural regeneration in a former mining area.

Following the review of parliamentary representation in Greater Manchester in 2009, the Boundary Commission for England recommended alterations to constituencies in the Wigan area. The electoral wards used in the altered Leigh constituency are:

• Astley, Mosley Common, Atherleigh, Golborne and Lowton West, Leigh East, Leigh South, Leigh West, Lowton East and Tyldesley, all from the Metropolitan Borough of Wigan.

The constituency was created in the Redistribution of Seats Act 1885 as a result of the South West Lancashire constituency being divided into eight single member seats. Between 1922 and December 2019, candidates belonging to the Labour Party had continuously served the seat, which for the political party made it one of their longest held constituencies. One recent Labour incumbent was Andy Burnham, Shadow Home Secretary from September 2015 to October 2016.

• List of parliamentary constituencies in Greater Manchester