1770 was a common year.
|Centuries:||17th century – 18th century – 19th century|
|Decades:||1740s 1750s 1760s – 1770s – 1780s 1790s 1800s|
|Years:||1767 1768 1769 – 1770 – 1771 1772 1773|
- March 5 – Boston Massacre: 5 Americans killed by British troops in an event that would help start the American Revolutionary War 5 years later.
- May 14 – Marie Antoinette arrives at the French court.
- May 16 – 14-year old Marie Antoinette marries 15-year old Louis-Auguste (who later becomes Louis XVI King of France).
- May 16 – Fireworks at the wedding of the crown prince of France in Paris cause a fire – 800 dead
- June 3 – Gasper de Portola and Father Junipero Serra establish Monterey, which was the capital of California from 1777-1849.
- July 1 – Comet Lexell (D/1770 L1) passes the Earth
- August 22 – James Cook claimed for Great Britain the eastern coast of New Holland (Australia)
- Joseph Priestley, British chemist, recommends the use of a rubber to remove pencil marks.
- Joseph Louis Lagrange proves Bachet's Conjecture.
- December 17 – Ludwig van Beethoven (baptised).