1703 (MDCCIII) was a common year starting on Monday of the Gregorian calendar and a common year starting on Friday of the Julian calendar, the 1703rd year of the Common Era (CE) and Anno Domini (AD) designations, the 703rd year of the 2nd millennium, the 3rd year of the 18th century, and the 4th year of the 1700s decade. As of the start of 1703, the Gregorian calendar was 11 days ahead of the Julian calendar, which remained in localized use until 1923. In the Swedish calendar it was a common year starting on Thursday, one day ahead of the Julian and ten days behind the Gregorian calendar.
|Ab urbe condita||2456|
|Balinese saka calendar||1624–1625|
|English Regnal year||1 Ann. 1 – 2 Ann. 1|
|Chinese calendar||壬午年 (Water Horse)|
4399 or 4339
— to —
癸未年 (Water Goat)
4400 or 4340
|- Vikram Samvat||1759–1760|
|- Shaka Samvat||1624–1625|
|- Kali Yuga||4803–4804|
|Japanese calendar||Genroku 16|
|Julian calendar||Gregorian minus 11 days|
|Minguo calendar||209 before ROC|
|Thai solar calendar||2245–2246|
1829 or 1448 or 676
— to —
1830 or 1449 or 677
|Wikimedia Commons has media related to 1703.|
- January 14 – The magnitude 6.7 Norcia earthquake affects Central Italy with a maximum Mercalli intensity of XI (Extreme). With a death toll of 6,240–9,761, it is the first in a sequence of three destructive events.
- January 16 – The magnitude 6.2 Montereale earthquake causes damage at Accumoli, Armatrice, Cittareale, and Montereale, with a maximum Mercalli intensity of VIII (Severe).
- January 30 (December 14 of previous year in the Chinese calendar) – In Japan, Forty-seven rōnin assassinate daimyō Kira Yoshinaka, the enemy of their former lord Asano Naganori, at his own mansion as a vengeance; 46 of the 47 samurai commit seppuku, a ritual suicide on March 20 (February 4 in the Chinese calendar).
- February – Soldiers at Fort Louis de la Mobile celebrate Mardi Gras in Mobile, starting the tradition for Mobile, Alabama.
- February 2 – The magnitude 6.7 L'Aquila earthquake affects Central Italy, with a maximum Mercalli intensity of X (Extreme). In the final large event (an example of Coulomb stress transfer), damage occurs as far distant as Rome, with landslides, liquefaction, slope failures and 2,500–3,000 deaths.
- April 21 – The Company of Quenching of Fire (i.e., a fire brigade) is founded in Edinburgh, Scotland.
- May 26 – Portugal joins the Grand Alliance.
- May 27 (May 16 OS) – The city of Saint Petersburg, Russia is founded, following Peter the Great's reconquest of Ingria from Sweden, during the Great Northern War.
- June 15 – Hungarians rebel under Prince Francis II Rákóczi.
- June – The completed Icelandic census of 1703 is presented in the Althing, the first complete census of any country.
- June 19 – Bavarian troops, who during the so-called Bavarian Rummel had invaded Tyrol, besiege Kufstein. Fires break out on the outskirts that engulf the town, destroy it and reach the powder store of the supposedly impregnable fortress. The enormous gunpowder supplies explode and Kufstein has to surrender on 20 June. That same day the Tyrolese surrender in Wörgl; two days later Rattenberg is captured and Innsbruck is cleared without a fight on 25 June.
- July 26 – After their victories at the Pontlatzer Bridge and the Brenner Pass, Tyrolese farmers drive out the Bavarian Elector, Maximilian II Emanuel, from North Tyrol and thus prevent the Bavarian Army, which is allied with France, from marching on Vienna during the War of the Spanish Succession. This success, at low cost, is the signal for the rebellion of the Tyrolese against Bavaria, and Elector Maximilian II Emanuel has to flee from Innsbruck. The Bavarian Army withdraws through Seefeld in Tirol back to Bavaria.
- July 29–31 – Daniel Defoe is placed in a pillory, then imprisoned for four months for the crime of seditious libel after publishing his satirical political pamphlet The Shortest Way with the Dissenters (1702) (his release is granted in mid-November).
- August 23 – Edirne event: Sultan Mustafa II of the Ottoman Empire is dethroned.
- September 7 – War of the Spanish Succession: The town of Breisach is retaken for France by Camille d'Hostun, duc de Tallard.
- September 12 – War of the Spanish Succession: Habsburg Archduke Charles is proclaimed King of Spain, but never exercises full rule.
- October – A whirlwind blows down the tower of the Gan Takal in Gondar, capital of Ethiopia, killing 30.
- November 15
- War of the Spanish Succession: Battle of Speyerbach (in modern-day Germany) – The French defeat a German relief army, allowing the French to take the besieged town of Landau two days later, for which Tallard is made a Marshal of France.
- Rákóczi's War of Independence: Battle of Zvolen (in modern-day Slovakia) – The Kurucs defeat the Austrians and their allies (Denmark, Hungary and the Serbs).
- November 19 – The Man in the Iron Mask dies in the Bastille, in France.
- November 30 – Isaac Newton is elected president of the Royal Society in London, a position he will hold until his death in 1727.
- December 7–10 (November 26–29 O.S.) – The Great Storm of 1703, an Atlantic hurricane, ravages southern England and the English Channel, killing at least 8,000, mostly at sea. The Eddystone Lighthouse off Plymouth is destroyed in the storm together with its designer Henry Winstanley.
- December 27 – Portugal and England sign the Methuen Treaty, which gives preference to Portuguese wines imported into England.
- December 28 – Ahmed III succeeds the deposed Mustafa II, as Ottoman Emperor.
- French-born imposter George Psalmanazar arrives in London.
- Between 1702 and 1703, an epidemic of smallpox breaks out in Quebec, in which 2,000-3,000 people die (300-400 in Quebec City).
- February 5 – Gilbert Tennent, Irish-born religious leader (d. 1764)
- March 5 (N. S.) – Vasily Trediakovsky, Russian poet (d. 1768)
- March 23 – Cajsa Warg, Swedish cookbook author (d. 1769)
- May 14 – David Brearly, delegate to the U.S. Constitutional Convention (d. 1785)
- June 26 – Thomas Clap, first president of Yale University (d. 1767)
- June 28 – John Wesley, English founder of Methodism and anti-slavery activist (d. 1791)
- August 2 – Lorenzo Ricci, Italian Jesuit leader (d. 1775)
- September 29 – François Boucher, French painter (d. 1770)
- October 5 – Jonathan Edwards, American preacher (d. 1758)
- October 13 – Andrea Belli, Maltese architect and businessman (d. 1772)
- October 28 – Antoine Deparcieux, French mathematician (d. 1768)
- November 25 – Jean-François Séguier, French astronomer and botanist (d. 1784)
- November 26 – Theophilus Cibber, English actor and writer (d. 1758)
- December 2 – Ferdinand Konščak, Croatian explorer (d. 1759)
- date unknown – Jack Broughton, English bare-knuckle fighter who produced the earliest known rules of boxing (d. 1789)
- date unknown – Fukuda Chiyo-ni, Japanese poet (d. 1775)
- January 9 – Úrsula Micaela Morata, Spanish writer (b. 1628)
- January 11 – Johann Georg Graevius, German classical scholar and critic (b. 1632)
- January 16 – Erik Dahlbergh, Swedish engineer, soldier and field marshal (b. 1625)
- February 15 – Robert Kerr, 1st Marquess of Lothian (b. 1636)
- February 18
- February 20 – John Churchill, Marquess of Blandford, British noble (b. 1686)
- February 28 – Sir Roger Twisden, 2nd Baronet of England (b. 1640)
- March 3 – Robert Hooke, English scientist (b. 1635)
- March 12 – Aubrey de Vere, 20th Earl of Oxford (b. 1627)
- March 31 – Johann Christoph Bach, German composer (b. 1642)
- April 1 – Thomas Jermyn, 2nd Baron Jermyn, Governor of Jersey (b. 1633)
- April 18 – Denis Granville, English priest (b. 1637)
- April 20 – Lancelot Addison, English royal chaplain (b. 1632)
- May 3 – Sir Richard Grobham Howe, 2nd Baronet, English Member of Parliament (b. 1621)
- May 6 – John Murray, 1st Marquess of Atholl (b. 1631)
- May 16 – Charles Perrault, French author (b. 1628)
- May 26
- June 14 – Jean Herauld Gourville, French adventurer (b. 1625)
- June 19 – William Stanhope, English politician (b. 1626)
- July 17 – Roemer Vlacq I, Dutch naval captain (b. 1637)
- July 20
- August 10 – Fuquan (prince), Chinese Qing Dynasty prince (b. 1653)
- August 21 – Thomas Tryon, British hat maker (b. 1634)
- September 22 – Vincenzo Viviani, Italian mathematician and scientist (b. 1622)
- September 25 – Archibald Campbell, 1st Duke of Argyll, Scottish privy councillor (b. 1658)
- September 29 – Charles de Saint-Évremond, French soldier (b. 1610)
- September 30 – Walter J. Johnson, English explorer, fur trader (b. 1611)
- October 3 – Alessandro Melani, Italian composer (b. 1639)
- October 8 – Tomás Marín de Poveda, 1st Marquis of Cañada Hermosa, Royal Governor of Chile (b. 1650)
- October 11 – Roger Cave, English politician (b. 1655)
- October 14 – Thomas Kingo, Danish bishop (b. 1634)
- October 24 – William Burkitt, English biblical expositor, vicar in Dedham (b. 1650)
- October 28 – John Wallis, English mathematician (b. 1616)
- November 19 – The Man in the Iron Mask (identity unknown)
- November 27 – Henry Winstanley, English engineer (b. 1644)
- November 30 – Nicolas de Grigny, French organist and composer (b. 1672)
- December 28 – Mustafa II, Ottoman Sultan (b. 1664)
- date unknown – Phetracha, king of Ayutthaya (b. 1632)
- Anastasiya Dabizha, princess of Moldavia and Wallachia and Hetmana of Ukraine.