1921 in Wales

Incumbents

• Archdruid of the National Eisteddfod of Wales – Dyfed
• Lord Lieutenant of Anglesey – Sir Richard Henry Williams-Bulkeley, 12th Baronet
• Lord Lieutenant of Brecknockshire – Joseph Bailey, 2nd Baron Glanusk
• Lord Lieutenant of Caernarvonshire – John Ernest Greaves
• Lord Lieutenant of Cardiganshire – Herbert Davies-Evans
• Lord Lieutenant of Carmarthenshire – John Hinds
• Lord Lieutenant of Denbighshire – Lloyd Tyrell-Kenyon, 4th Baron Kenyon
• Lord Lieutenant of Flintshire – Henry Gladstone, later Baron Gladstone
• Lord Lieutenant of Glamorgan – Robert Windsor-Clive, 1st Earl of Plymouth
• Lord Lieutenant of Merionethshire – Sir Osmond Williams, 1st Baronet
• Lord Lieutenant of Monmouthshire – Ivor Herbert, 1st Baron Treowen
• Lord Lieutenant of Montgomeryshire – Sir Herbert Williams-Wynn, 7th Baronet
• Lord Lieutenant of Pembrokeshire – John Philipps, 1st Viscount St Davids
• Lord Lieutenant of Radnorshire – Arthur Walsh, 3rd Baron Ormathwaite
• Archbishop of Wales – Alfred George Edwards, Bishop of St Asaph

Events

• 26 January - The Abermule train collision claims 17 lives, including that of the chairman of the rail company, Lord Herbert Vane-Tempest.
• 18 February - by-election: 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.
• 7 March - Francis Edward Mostyn is appointed Roman Catholic Archbishop of Cardiff.
• 1 April - Alfred Mond becomes Minister of Health.
• 1 April-28 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".
• 4 June - Cardiologist Thomas Lewis is awarded a knighthood in King George V's Birthday Honours.
• December - Leslie Morris becomes a founder member of the Communist Party of Canada.
• date unknown
• *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, which forms the basis for the development of Plaid Cymru.
• *John Bodvan Anwyl is appointed secretary of the Welsh dictionary project sponsored by the Board of Celtic Studies of the University of Wales.

Arts and literature

Awards

• National Eisteddfod of Wales
• National Eisteddfod of Wales: Chair - Robert John Rowlands, "Min y Môr"
• National Eisteddfod of Wales: Crown - Albert Evans-Jones

New books

English language

• Edwin Sidney Hartland - primitive society
• Evan Frederic Morgan, 2nd Viscount Tredegar - Trial by Ordeal
• Margaret Haig Thomas, Viscountess Rhondda - D. A. Thomas, Viscount Rhondda, by his Daughter and Others
• Francis Brett Young - ''The Black Diamond''

Welsh language

• Edward Tegla Davies - Tir Y Dyneddon
• John Evan Davies - Blodau'r Grug
• Moelona - ''Y Wers Olaf''

New drama

• Saunders Lewis - ''The Eve of St John''

Music

• 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.

Film

• A teenage Roger Livesey makes his screen debut in The Four Feathers and in the same year appears in a film version of Where the Rainbow Ends.

Sport

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

Births

• 5 February - Marion Eames, novelist
• 16 February - Bob Evans, rugby union international
• 19 March - Tommy Cooper, comedian
• 3 March - David James, cricketer
• 21 March - Antony Hopkins, composer, pianist, conductor and broadcaster
• 4 April - Eileen Beasley, teacher and campaigner
• 9 April - Jack Jones, footballer
• 6 May - Ted Morris, footballer
• 21 May - Leslie Norris, poet
• 28 May - Rhys Probert, aeronautical engineer
• 4 June - Allen Forward, Wales international rugby union player
• 8 June - Alwyn Williams, geologist
• 28 June - R. Tudur Jones, theologian
• 16 August - Roger Ashton (footballer), footballer
• 31 August - Raymond Williams, academic and writer
• 8 September - Sir Harry Secombe, entertainer
• 13 September - Handel Greville, Wales international rugby union player
• 15 September - Billy Cleaver, Wales international rugby union player and colliery manager
• 12 October - Kenneth Griffith, actor and director
• 3 October – Graham Davies, footballer
• 18 October – Billy James, footballer
• 17 December - Ron Davies, photographer
• 21 December - T. Harri Jones, poet and academic

Deaths

• 11 February - William Evans (Tonyrefail), minister and author, 82
• 25 February - John Thomas of Llanwrtyd, composer, 81
• 29 April - Billy Matthews, footballer, 37/38
• 6 June - James Havard Thomas, sculptor, 66
• 5 July - Alfred Onions, politician, 62
• 13 July - Emily Davies, educationist, 90
• 21 July - Tom Deacon - Wales international rugby union player
• 27 July
• *John Jones (Myrddin Fardd), author, 85
• * - James Winstone, miners' leader and politician, 58
• 6 August - Sir David Brynmor Jones QC, lawyer and historian, 68 or 69
• 23 August - Francis Jayne, bishop and academic, 76
• 31 August - Thomas Rees, mayor of Brisbane, Australia, 76
• 3 October - William Rhys-Herbert, composer, conductor, organist and pianist, 53
• 9 October - Gwyneth Bebb, lawyer, 31
• 11 October - Willie Thomas, Wales international rugby captain, 55
• 12 November - Edward Windsor Richards, engineer, 90
• 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