1921 in Wales

Centuries:	18th; 19th; 20th; 21st; ;
Decades:	1900s; 1910s; 1920s; 1930s; 1940s;
See also:	List of years in Wales; Timeline of Welsh history 1921 in The United Kingdom Scotland Elsewhere

This article is about the particular significance of the year 1921 to Wales and its people.

Incumbents

26 January - The Abermule train collision claims 17 lives, including that of Lord Herbert Vane-Tempest, youngest son of the Marquess of Londonderry.
February - Ernest Evans becomes Liberal MP for Cardiganshire, winning the seat vacated by Matthew Vaughan-Davies, 1st Baron Ystwyth, on the latter's elevation to the peerage.
1 April - Alfred Mond becomes Minister of Health.
April–June - Lockout in the coal mining industry; A. J. Cook, the miner's leader, is sentenced to two months’ imprisonment for "inciting to unlawful assembly".
December - Leslie Morris becomes a founder member of the Communist Party of Canada.
23 December - The Maid of Delos sinks off the coast of Dyfed, with 26 deaths.
The Anglo-Persian Oil Company Limited begins work on the UK's first oil refinery at Llandarcy.
Last copper smelting in the Lower Swansea valley.
Hugh Robert Jones founds the Byddin Ymreolaeth Cymru (“Home Rule Army”), which forms the basis for the development of Plaid Cymru.
Cardiologist Thomas Lewis is knighted.
John Bodvan Anwyl is appointed secretary of the Welsh dictionary project sponsored by the Board of Celtic Studies of the University of Wales.
Francis Edward Mostyn becomes Roman Catholic Archbishop of Cardiff.

Ivor Novello & Dion Titheradge - "And Her Mother Came Too"
The composer Peter Warlock returns to the family home at Cefn-bryntalch Hall, near Abermule, where he will stay until June 1924.

Cricket - Glamorgan CCC is admitted to crickets County Championship competition for the first time.

11 February - William Evans (Tonyrefail), minister and author, 82
25 February - John Thomas of Llanwrtyd, composer, 81
6 July - Alfred Onions, politician, 62
15 August (at Ilfracombe) - Sir David Brynmor Jones QC, lawyer and historian, 68 or 69
21 July - Tom Deacon - Wales international rugby union player
27 July - John Jones (Myrddin Fardd), author, 85
27 July (in London) - James Winstone, miners' leader and politician, 58
23 August (in Oswestry) - Francis Jayne, bishop and academic, 76
11 October - Willie Thomas, Wales international rugby captain, 55
15 December - Hopkin Maddock, Wales international rugby player, 40
16 December - Owen Morgan, journalist, 85
21 December - Joseph Morewood Staniforth, editorial cartoonist, 57 or 58