|Covid-19|January 25 (Tatiana Day) – Moscow University is established.
February 13 – The kingdom of Mataram on Java is divided in two, creating the sultanate of Yogyakarta and the sunanate of Surakarta.
February 20 – General Braddock lands in Virginia to take command of the British forces against the French in North America.
April 2 – A naval fleet led by Commodore William James of the East India Company captures Tulaji Angre's fortress Suvarnadurg from the Marathas.
April 15 – A Dictionary of the English Language is published by Samuel Johnson (he had begun the work 9 years earlier, in 1746).
July 9 – French and Indian War – Braddock Expedition: British troops and colonial militiamen are ambushed and suffer a devastating defeat inflicted by French and Indian forces. During the battle, British General Edward Braddock is mortally wounded. Colonel George Washington survives.
July 17 – In a convoy of ships from Great Britain, returning to India for the East India Company, the lead ship Dodington wrecks at Port Elizabeth, losing a chest of gold coins from Robert Clive, worth £33,000. In 1998, 1,400 coins are offered for sale, and in 2002 a portion is given to the South African government.
July 25 – The decision to deport the Acadians is made during meetings of the Nova Scotia Council meeting in Halifax. From September 1755 to June 1763 the vast majority of Acadians are deported to one of the following British Colonies in America: Massachusetts, Connecticut, New York, Pennsylvania, Maryland, Virginia, North Carolina and South Carolina and Georgia. Contrary to popular belief, no Acadians are sent to Louisiana. Those sent to Virginia are refused and then sent on to Liverpool, Bristol, Southampton and Penryn in England. In 1758 the Fortress of Louisbourg falls and all of the civilian population of Isle Royal (Cape Breton Island) and Isle St. Jean (Prince Edward Island) are repatriated to France. Among them were several thousand Acadians who had escaped the deportation by fleeing into those areas. Very few Acadians successfully escape the deportation and do so only by fleeing into some of the northern sections of present day New Brunswick. The event inspires Longfellow to write the epic poem Evangeline.
August 10 – The Expulsion of the Acadians begins with the Bay of Fundy Campaign.
November 1 – 1755 Lisbon earthquake: In Portugal, Lisbon is destroyed by a massive earthquake and tsunami, killing 60,000–90,000 people.
November 18 – An earthquake occurs in the vicinity of Cape Ann, Massachusetts, causing extensive damage.
November 25 – King Ferdinand VI of Spain grants the Religious of the Virgin Mary in the Philippines royal protection.
December 2 – The second Eddystone Lighthouse off the coast of England is destroyed by fire.
Wolsey, the clothes manufacturer, is established in Leicester, England; the business celebrates its 250th anniversary in 2005.
Construction of the Puning Temple complex in Chengde, China is complete, during the reign of the Qianlong Emperor.
Construction of St Ninian's Church, Tynet, Scotland, the country's oldest surviving post-Reformation Roman Catholic clandestine church.
Joseph Black describes his discovery of carbon dioxide ("fixed air") and magnesium in a paper to the Philosophical Society of Edinburgh.
The brine shrimp Artemia salina is first described, in Linnaeus' Systema Naturæ.
January 11 – Alexander Hamilton, first U.S. Secretary of the Treasury (most cited date of birth) (d. 1804)
January 25 – Paolo Mascagni, Anatomist (d. 1815)
February 11 – Albert Christoph Dies, German composer (d. 1822)
March 24 – Rufus King, American lawyer, politician, and diplomat (d. 1827)
April 3 – Simon Kenton, Frontiersman; Revolutionary Militia General (d. 1836)
April 10 – Samuel Hahnemann, founder of homeopathy (d. 1843)
April 11 – James Parkinson, English surgeon, apothecary, geologist, palaeontologist, and political activist (d. 1824)
April 16 – Louise Élisabeth Vigée Le Brun, French painter (d. 1842)
May 21 – Alfred Moore, American judge and Associate Justice of the Supreme Court of the United States (d. 1810)
June 6 – Nathan Hale, American Revolutionary War captain, writer and patriot (d. 1776)
June 15 – Antoine François, comte de Fourcroy, French chemist (d. 1809)
June 30 – Paul François Jean Nicolas, vicomte de Barras, French politician (d. 1829)
September 9 – Benjamin Bourne, American politician (d. 1808)
September 13 – Oliver Evans, American inventor, engineer and businessman (d. 1819)
September 24 – John Marshall, American jurist, and Chief Justice of the United States (d. 1835)
November 1 – Henriette von Crayen, German salonniére (d. 1832)
November 2 – Marie Antoinette, Queen of France (d. 1793)
November 12 – Gerhard von Scharnhorst, Prussian general (d. 1813)
Louis XVIII of France (d. 1824)
Charles Manners-Sutton, Archbishop of Canterbury (d. 1828)
date unknown – Maria Elizabetha Jacson, British botanist (d. 1829)
December 3 – Gilbert Stuart, an American painter from Rhode Island (d. 1828)
February 10 – Montesquieu, French writer (b. 1689)
February 11 – Francesco Scipione, marchese di Maffei, Italian archaeologist (b. 1675)
March 2 – Louis de Rouvroy, duc de Saint-Simon, French writer (b. 1675)
April 6 – Richard Rawlinson, English minister and antiquarian (b. 1690)
June 26 – Iyasu II, Emperor of Ethiopia (b. c. 1723)
July 13 – Edward Braddock, British general (b. c. 1695)
August 13 – Francesco Durante, Italian composer (b. 1684)
September 8 – Ephraim Williams, American philanthropist (b. 1715)
September 9 – Johann Lorenz von Mosheim, German historian (b. 1694)
October 16 – Gerard Majella, Catholic saint (b. 1725)
October 22 – Elisha Williams, American rector of Yale College (b. 1694)
November 25 – Johann Georg Pisendel, German musician (b. 1687)
December 1 – Maurice Greene, English composer (b. 1696)
approximate date – Queen Nanny of the Maroons, Jamaican National Heroine (b. 1686)
Cai Wan, politically influential Chinese poet (b. 1695)
1755 (MDCCLV) was a common year starting on Wednesday (dominical letter E) of the Gregorian calendar and a common year starting on Sunday (dominical letter A) of the Julian calendar, the 1755th year of the Common Era (CE) and Anno Domini (AD) designations, the 755th year of the 2nd millennium, the 55th year of the 18th century, and the 6th year of the 1750s decade. As of the start of 1755, the Gregorian calendar was 11 days ahead of the Julian calendar, which remained in localized use until 1923.