Central Ayrshire is a constituency of the British House of Commons, located in the south-west of Scotland within the North Ayrshire and South Ayrshire council areas. It elects one Member of Parliament (MP) at least once every five years using the first-past-the-post system of voting.

1950–1974: The burghs of Irvine, Kilwinning, Stewarton and Troon, the districts of Irvine and Kilbirnie, the electoral division of Dundonald in the district of Ayr, and the electoral division of Dunlop and Stewarton in the district of Kilmarnock.^[2]

1974–1983: The burghs of Irvine, Kilwinning and Troon, the districts of Irvine and Kilbirnie and the electoral division of Dundonald in the district of Ayr.^[3]

As created in 1950, the constituency merged parts of the Bute and Northern Ayrshire and Kilmarnock constituencies. Following the Representation of the People Act 1948, the Central Ayrshire constituency between 1950 and 1955 consisted of Irvine, Kilwinning, Stewarton, Troon, Kilbirnie and part of the district of Kilmarnock.^[4] When abolished in 1983, the constituency was largely replaced by Cunninghame South, with Troon and its surrounding areas forming part of the Ayr constituency.

The constituency was re-established in 2005, centred around the historic burgh of Irvine and stretching north to cover part of Kilwinning and south to cover the coastal resort towns of Prestwick, Troon and their adjacent hinterlands alongside part of Ayr. The constituency covers the 2017 electoral wards of Irvine East, Irvine South, Irvine West and a small section of Kilwinning (between the River Garnock and the B778) from the North Ayrshire Council area and Prestwick, Troon, Kyle and a small section of Ayr North (between Seaforth Road and Lochside Road in Heathfield) from the South Ayrshire Council area.^[5] The remainder of the North Ayrshire Council area is represented as part of the North Ayrshire and Arran Parliamentary constituency, with the remainder of South Ayrshire being covered by the Ayr, Carrick and Cumnock Parliamentary constituency alongside parts of East Ayrshire.

The constituency covers towns such as Irvine and parts of Kilwinning to the north, as well as the coastal resorts of Troon and Prestwick to the south. The seat also takes in a set of villages in rural South Ayrshire including the former mining communities of Annbank, Mossblown and Tarbolton alongside the villages of Loans, Dundonald and Symington.

Irvine was designated in the 1970s as a Glasgow overspill new town. In recent local council elections, the SNP have performed strongly in the town of Irvine gaining 3 Councillors to Labours 5 in Irvine and Kilwinning wards.

The coastal towns of Prestwick and Troon join the town as part of the constituency as well as outlying rural areas located south and east of Troon and Prestwick: Prestwick, Troon and their hinterlands have sustained a considerable level of support for Conservative candidates locally and as part of the Ayr constituency in the Scottish Parliament. Heathfield in Ayr North also forms part of the constituency: this area is relatively small but has been more supportive of the SNP in recent council elections.