About

Siân Gwenllian represents the Gwynedd Maldwyn constituency in the Senedd/Welsh Parliament, having previously represented Arfon from 2016 to 2026. She was first elected to the Senedd in 2016 and re-elected in 2021 with a higher percentage of the vote than any other candidate in Wales, doubling her majority with 63.3% of the vote. In the 2026 Senedd election, she was returned as one of the six Members of the Senedd for the new Gwynedd Maldwyn constituency under Wales’s reformed proportional electoral system.
 
She is proud to have successfully campaigned for a new medical school for north Wales, based in Bangor within her former Arfon constituency.
 
Following the 2026 Senedd election and the formation of the first Plaid Cymru-led Welsh Government, Siân was appointed Cabinet Minister for Local Government, Housing and Planning. She had previously held the Housing and Planning portfolio for Plaid Cymru (2024–2026), following her role as the Lead Designated Member in the Co-operation Agreement between Plaid Cymru and the Welsh Government (2021–2024).
 
During that period, she worked across 46 policy areas, helping to deliver major changes such as free school meals for all primary school pupils, the expansion of free childcare, radical measures to address the housing crisis, and reforms aimed at creating a more effective and representative Senedd.
 
During the fifth and sixth Senedd terms, she held various policy portfolios for Plaid Cymru, including Education, Local Government, Planning, the Welsh Language, and Culture. She also served as the party’s Senedd Commissioner, Trefnydd, Chief Whip, and Deputy Leader in the Senedd. Since 2024, she has been Plaid Cymru’s Director of Policy on the party’s National Executive Committee.
 
She grew up in the village of Y Felinheli, where she still lives, and received her secondary education in Bangor. She attended university in both Aberystwyth and Cardiff, and worked as a journalist with the BBC, HTV, and Golwg, as well as presenting and producing documentaries on a freelance basis. She also served as Press Officer for Cyngor Gwynedd from 1997 to 2004.
 
In 2008, Siân was elected county councillor for Y Felinheli, serving for eight years prior to her election to the Senedd. She held the finance portfolio from 2010 to 2012 before becoming the Council’s Deputy Leader and Cabinet Member for Education, Children and Young People. She was also the county’s Small Business Champion.
 
Siân’s political involvement spans several decades. During her time at Aberystwyth University, she was Deputy President of the Students’ Union. She has also served as a primary and secondary school governor, chaired her local community council, and volunteered with many local organisations. She has been a passionate campaigner for women’s equality and the Welsh language for more than 45 years.
 
Siân had four children with her husband, Dafydd. In 1999, when their youngest son was only three years old, Dafydd died of cancer. Siân subsequently raised their four children as a single parent.