Vale of Glamorgan (Welsh: Bro Morgannwg) is a constituency^{[n 1]} represented in the House of Commons of the UK Parliament since 2010 by Alun Cairns, a Conservative.^{[n 2]}

It is a bellwether constituency, having been won by the party with a plurality of seats in every general election since the seat was created in 1983.

The constituency is to retain its name but its boundaries altered, as part of the 2023 Periodic Review of Westminster constituencies and under the June 2023 final recommendations of the Boundary Commission for Wales for the next United Kingdom general election.^[3]

1983–2010: The Borough of Vale of Glamorgan wards of Baruc, Buttrills, Cadoc, Castleland, Court, Cowbridge, Dinas Powys, Dyfan, Gibbonsdown, Illtyd, Llandow, Llantwit Major, Peterson-super-Ely, Rhoose, St Athan, Sully, and Wenvoe.

2010–present: The Vale of Glamorgan County Borough electoral divisions of Baruc, Buttrills, Cadoc, Castleland, Court, Cowbridge, Dinas Powys, Dyfan, Gibbonsdown, Illtyd, Llandow and Ewenny, Llantwit Major, Peterston-super-Ely, Rhoose, St Athan, St Bride's Major, and Wenvoe.

This marginal constituency to the west of Cardiff takes in the Labour-voting seaside resort of Barry and a number of Conservative villages and small towns, such as Cowbridge. There have been some close shaves for both parties here in the past: Conservative Walter Sweeney got home by a mere 19 votes in 1992; and John Smith (the namesake of the late previous Labour leader) had a majority of under 2,000 in 2005. John Smith stood down from Parliament due to ill health, and the seat went Conservative at the 2010 election.

Sully ward was transferred to Cardiff South and Penarth in 2010.

• Vale of Glamorgan (Senedd constituency)
• List of parliamentary constituencies in South Glamorgan
• List of parliamentary constituencies in Wales