1649 (MDCXLIX) was a common year starting on Friday of the Gregorian calendar and a common year starting on Monday of the Julian calendar, the 1649th year of the Common Era (CE) and Anno Domini (AD) designations, the 649th year of the 2nd millennium, the 49th year of the 17th century, and the 10th and last year of the 1640s decade. As of the start of 1649, the Gregorian calendar was 10 days ahead of the Julian calendar, which remained in localized use until 1923.

• January 30 – King Charles I of England, Scotland and Ireland is beheaded. His widow Henrietta Maria lives in her native France.
• January 30 – The Commonwealth of England, a republican form of government, replaces the monarchy as the form of government of England and later of Scotland and Ireland. Members of the Long Parliament serve as government.
• January 30 – Prince Charles Stuart declares himself King Charles II of England, Scotland and Ireland. At the time all three Kingdoms had not recognized him as ruler.
• February 5 – In Edinburgh, Scotland claimant King Charles II of England is declared King in his absence. Scotland is the first of the three Kingdoms to recognize his claim to the throne.
• March 11 – The Frondeurs (rebels) and the French government sign the Peace of Rueil.
• March 19 – The House of Commons pass an act abolishing the House of Lords, declaring that it is "useless and dangerous to the people of England".
• May 17 – Banbury mutiny ends – leaders of the Leveller mutineers in the New Model Army are hanged
• May 19 – An act declaring England to be a Commonwealth is passed by the Rump Parliament.

• Robert Blake is promoted to become an Admiral of the English fleet
• August 15 – Admiral Robert Blake blockades Prince Rupert to allow Oliver Cromwell to land in Dublin and begin the Cromwellian conquest of Ireland
• September 2 – The Italian city of Castro is completely destroyed by the forces of Pope Innocent X, ending the Wars of Castro.
• Unknown date – Urga founded (now Mongolian capital)
• Digger movement crushed at St George's Hill

• February 2 – Pope Benedict XIII
• February 8 – Gabriel Daniel, French Jesuit historian
• February 11 – William Carstares, Scottish minister
• April 5 – Elihu Yale, American benefactor of Yale University
• April 9 – James Scott, 1st Duke of Monmouth, claimant to the thrones of England, Scotland, and Ireland
• June 13 – Adrien Baillet, French scholar and critic
• July 23 – Pope Clement XI
• September 15 – Titus Oates, English minister and plotter
• December 7 – Charles Garnier, French Jesuit missionary

• January 30 – King Charles I of England, Scotland, and Ireland (executed)
• March 9 – James Hamilton, 1st Duke of Hamilton, Scottish statesman
• March 9 – Henry Rich, 1st Earl of Holland, English soldier (executed)
• March 16 – Jean de Brébeuf, French Jesuit missionary
• March 19 – Gerhard Johann Vossius, German classical scholar and theologian
• March 26 – John Winthrop First Governor of Massachusetts Bay Colony
• May 14 – Friedrich Spanheim, Dutch theologian
• June 3 – Manuel de Faria e Sousa, Portuguese historian and poet
• September 6 – Robert Dudley, styled Earl of Warwick, English explorer and geographer
• September 15 – John Floyd, English Jesuit preacher
• October 3 – Giovanni Diodati, Swiss Protestant clergyman
• October 16 – Isaac van Ostade, Dutch painter
• November 19 – Caspar Schoppe, German scholar
• December 4 – William Drummond of Hawthornden, Scottish poet
• December 8 – Noël Chabanel, French Jesuit missionary