Caerphilly (Welsh: Caerffili) is a constituency[n 1] centred on the town of Caerphilly in South Wales, represented in the House of Commons of the UK Parliament since 2024 by Chris Evans of the Labour Party.

[n 2] Since its creation, the constituency has always elected Labour MPs, although the predecessor constituency of East Glamorganshire, and prior to that Glamorganshire had elected Liberal MPs throughout the Victorian era.

In the northwestern portion of the constituency are communities such as Hengoed and Ystrad Mynach, extending in a southeasterly direction through Caerphilly and Llanbradach to the rural outcrops bordering Cardiff.

[2] 2010–2024: The Caerphilly County Borough wards of Aber Valley, Aberbargoed and Bargoed, Bedwas and Trethomas, Gilfach, Hengoed, Llanbradach, Machen and Rudry, Morgan Jones, Nelson, Penyrheol, St Cattwg, St Martins, Van, and Ystrad Mynach.

2024–present: The Caerphilly County Borough wards of Aber Valley, Bedwas and Trethomas, Cefn Fforest and Pengam, Hengoed, Llanbradach, Machen and Rudry, Maesycwmmer, Morgan Jones, Nelson, Penyrheol, Pontllanfraith, St Cattwg, St Martins, Van, Ynysddu, and Ystrad Mynach.