Events from the year 1643 in England. This is the second year of the First English Civil War, fought between Roundheads (Parliamentarians) and Cavaliers (Royalist supporters of King Charles I).

• Monarch – Charles I

• 19 January – First English Civil War: Royalist victory at the Battle of Braddock Down secures dominance in Cornwall.
• 23 January – First English Civil War: Leeds falls to Parliamentary forces.^[1]
• 13 March – First English Civil War: Royalist victory at the First Battle of Middlewich in Cheshire.
• 18 March – Irish Confederate Wars: Battle of New Ross in Ireland – English troops defeat those of Confederate Ireland.^[2]
• 19 March – First English Civil War: Royalist victory at the Battle of Hopton Heath in Staffordshire, but the Royalist commander, the Earl of Northampton, is killed.^[2]
• 25 April – First English Civil War:
  • Reading falls to Parliament after the Siege of Reading.^[2]
  • Despite being vastly outnumbered, a Parliamentarian force under James Chudleigh defeats a Royalist army near Okehampton in Devon, at the Battle of Sourton Down.
• 8 May – First English Civil War: The first siege of Wardour Castle in Wiltshire ends after 6 days with the surrender of the Royalist garrison under Lady Blanche Arundell.
• 13 May – First English Civil War: Parliamentary forces led by Oliver Cromwell defeat Royalist forces at Grantham.^[1]
• 16 May – First English Civil War: Royalist victory at the Battle of Stratton confirms dominance in Cornwall and Devon.
• 21 May – First English Civil War: Capture of Wakefield by an outnumbered force of Parliamentarians from the Royalist defenders.^[3]
• 14 June – Licensing Order of 1643 passed by Parliament to censor newspapers.^[2]
• 18 June – First English Civil War: Royalist victory at the Battle of Chalgrove Field in Oxfordshire.^[2]
• 30 June – First English Civil War: Royalist victory at the Battle of Adwalton Moor gives control of Yorkshire.^[2]
• 1 July – the Westminster Assembly of theologians ("divines") and parliamentarians is convened at Westminster Abbey with the aim of restructuring the Church of England.
• 5 July – First English Civil War: pyrrhic Royalist victory at the Battle of Lansdowne near Bath, Somerset.^[2]
• 13 July – First English Civil War: Royalist cavalry led by Henry Wilmot, newly created Baron Wilmot, win a crushing victory at the Battle of Roundway Down near Devizes over Parliamentarians led by Sir William Waller.^[2]
• 26 July – First English Civil War: Royalists capture Bristol.^[4]
• 28 July – First English Civil War: Parliamentary victory at the Battle of Gainsborough.^[2]
• 18 August – Parliament passes "An Ordinance for Explanation of a former Ordinance for Sequestration of Delinquents Estates with some Enlargements", including an "Oath of Abjuration" of the Pope.
• c. 26 August – Parliament passes an ordinance for the cleansing of churches from altars and other monuments of "superstition" or "idolatry".^[5]
• 20 September – First English Civil War: strategic Parliamentary victory at the First Battle of Newbury over Royalist forces led personally by the king.^[1]
• 25 September – the Solemn League and Covenant is signed between the Parliament of England and the Parliament of Scotland.^[1]
• 11 October – First English Civil War: Parliamentary victory at the Battle of Winceby in Lincolnshire.^[2]
• 13 December – First English Civil War: Parliamentary victory at the Battle of Alton in Hampshire.^[2]
• 25 December – Christmas Island is sighted and named by Captain William Mynors of the English East India Company's ship Royal Mary.^[6]
• 27 December – First English Civil War: Royalist victory at the Second Battle of Middlewich.^[2]

• Cromwell's Soldiers' Pocket Bible.
• Dr Thomas Browne's spiritual testament Religio Medici ("true and full coppy").

• 4 January (N.S.) – Isaac Newton, mathematician and physicist (died 1727)
• 16 February – John Sharp, Archbishop of York (died 1714)
• 1 November – John Strype, historian and biographer (died 1737)

• 14 January – John Bois, Bible translator (born 1560)
• 2 March – Robert Greville, 2nd Baron Brooke, Parliamentary General, killed by sniper (born 1608)
• 19 March – Spencer Compton, 2nd Earl of Northampton, soldier and politician, killed in action (born 1601)
• 24 June – John Hampden, parliamentarian, died of wounds (born c. 1595)
• 5 July – Bevil Grenville, soldier (born 1595)
• 25 July – Robert Pierrepont, 1st Earl of Kingston-upon-Hull, statesman (born 1584)
• 20 August – Anne Hutchinson, Puritan preacher (born 1591)
• 20 September, at the First Battle of Newbury:
  • Lucius Cary, 2nd Viscount Falkland, politician, soldier and author (born c. 1610)
  • Robert Dormer, 1st Earl of Carnarvon (born 1610)
  • Henry Spencer, 1st Earl of Sunderland (born 1620)
• 3 November – John Bainbridge, astronomer (born 1583)
• 29 November – William Cartwright, dramatist (born 1611)
• 8 December – John Pym, statesman (born 1583)
• approx. date – Henry Glapthorne, dramatist (born 1610)