UK general election on 7 May 2015 Elections won by Plaid Cymru
A general election to the 56th Parliament of the United Kingdom with an electorate of 46,354,197, having 30,697,525 valid votes and 102,639 invalid votes.
Read the House of Commons Library briefing.
| Constituency | Candidate | Electorate | Turnout | Votes | Vote share | Vote change | Majority |
| Arfon | WILLIAMS, Hywel | 40,492 | 66.3% | 11,790 | 43.9% | 8.0% | 3,668 |
| Carmarthen East and Dinefwr | EDWARDS, Jonathan | 55,750 | 70.7% | 15,140 | 38.4% | 2.8% | 5,599 |
| Dwyfor Meirionnydd | SAVILLE-ROBERTS, Liz | 44,394 | 65.1% | 11,811 | 40.9% | -3.5% | 5,261 |
Turnout as calculated by the House of Commons Library, is the total number of votes cast and not spoiled, divided by the size of the electorate.