Hornchurch and Upminster is a constituency^{[n 1]} in Greater London represented in the House of Commons of the UK Parliament^{[n 2]} by Julia Lopez, a member of the Conservative Party, currently Minister of State for Media, Tourism and Creative Industries, who succeeded Angela Watkinson in 2017. Watkinson had been elected in 2010 as the constituency's first MP.

2010–present: The London Borough of Havering wards of Cranham, Emerson Park, Gooshays, Hacton, Harold Wood, Heaton, St Andrew's, Upminster.

The seat was the proposal of the Boundary Commission's Fifth Periodic Review of Westminster constituencies in 2008–9 and was after consultation accepted by Parliament. Hornchurch and Upminster is essentially an expansion of the old Upminster seat to include a chunk of the old Hornchurch seat, specifically Hornchurch itself. Most of the western wards of Hornchurch went to the new Dagenham and Rainham seat. The electoral wards in Havering were redrawn in 2022 and subsequently the constituency no longer aligns with ward boundaries.

The easternmost seat in Greater London, it includes the suburbs of Cranham, Emerson Park, Harold Wood, Hornchurch, Upminster and part of Elm Park. The constituency includes the semi-rural Noak Hill and North Ockendon and the large Harold Hill estate, built by the London County Council and completed in 1958.

There are London Underground stations at Hornchurch, Upminster, Upminster Bridge and another on the boundary at Elm Park. Harold Wood is served by a station on the Elizabeth line and there is a London Overground station at Emerson Park. Upminster is an interchange station with National Rail services on the Fenchurch Street line as well as London Underground and London Overground services.

Pockets of deprivation exist in the north of the constituency.^[5] Most output areas have high levels of retired constituents by Greater London standards, and the borough as a whole is similar to the London Borough of Bromley in that it has high levels of home ownership, on statistics compiled in the 2011 UK Census. The seat, like the London borough, is the only one in London that extends beyond the M25 motorway.^[6]

The predecessor seats were lost by the Conservatives in Labour's landslide 1997 victory, but Upminster was one of the few Conservative gains in 2001 and Hornchurch was lost by Labour in 2005; this area is now very safe territory for the Conservatives since it gained their strongest areas from Hornchurch in the boundary changes. The 2015 result made the seat the 146th safest of the Conservative Party's 331 seats by percentage of majority.^[7] At the 2015 general election, the constituency was one of five in Greater London where the UK Independence Party came in second place.^[8]

The constituency is unusual in that for local elections to Havering Council, the Havering Residents Association dominates the results rather than the Conservative Party who have held the seat since it was created.