Dwyfor Meirionnydd is a constituency of the House of Commons of the Parliament of the United Kingdom (at Westminster). The seat was created by the Welsh Boundary Commission for the 2010 general election, and replaced the old north Wales seat of Meirionnydd Nant Conwy. Dwyfor Meirionnydd is bordered to the north by Arfon and Aberconwy. The same boundaries were used for the Dwyfor Meirionnydd Welsh Assembly constituency in the 2007 Welsh Assembly election.

Like its predecessors, it is a Plaid Cymru stronghold, with their candidate in 2019 achieving a majority of 15.9%.

The constituency is to retain its name and gain wards, 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 2024 United Kingdom general election.^[2]

The constituency was created by merging most of Meirionnydd Nant Conwy with the southern part of Caernarfon; the northern area became part of a new Arfon constituency.

The electoral wards used to create the seat are as follows. They are entirely within the preserved county of Gwynedd.

• Aberdaron, Aberdyfi, Abererch, Abermaw, Abersoch, Bala, Botwnnog, Bowydd and Rhiw, Brithdir and Llanfachreth/Ganllwyd/Llanelltyd, Bryn-crug/Llanfihangel, Clynnog, Corris/Mawddwy, Criccieth, Diffwys and Maenofferen, Dolbenmaen, Dolgellau North, Dolgellau South, Dyffryn Ardudwy, Efail-newydd/Buan, Harlech, Llanaelhaearn, Llanbedr, Llanbedrog, Llandderfel, Llanengan, Llangelynin, Llanuwchllyn, Llanystumdwy, Morfa Nefyn, Nefyn, Penrhyndeudraeth, Porthmadog East, Porthmadog West, Porthmadog-Tremadog, Pwllheli North, Pwllheli South, Teigl, Trawsfynydd, Tudweiliog and Tywyn.

• Dwyfor Meirionnydd (Senedd constituency)
• List of parliamentary constituencies in Gwynedd
• List of parliamentary constituencies in Wales