Events from the year 1742 in Sweden

• Monarch – Frederick I

• - The Kosta Glasbruk is founded.
• June - The Swedish province of Finland is occupied of the Empire of Russia during the Lesser Wrath.
• 9 August - The Swedish forces in Finland surrender to the Russian army in Helsingfors.
• - Empress Elizabeth I of Russia states that Sweden may have Finland back if her candidate in the election for an heir to the Swedish throne, Adolf Frederik of Holstein-Gottorp, is accepted.
• - Proclamation of the Kingdom of Finland (1742)
• - The Hats (party) lose government power and are replaced by a government supported by the Caps (party).
• - Anders Celsius construct the Celsius thermometer.
• - Adelriks och Giöthildas äfwentyr by Jacob Henrik Mörk.

• 28 July - Rutger Macklean, driving figure in the reorganization of agricultural lands (died 1816)
• 3 October - Anders Jahan Retzius, scientist (died 1821)
• - Christina Krook, educator (died 1806)
• 9 December – Carl Wilhelm Scheele, chemist (died 1786)

• 17 April – Arvid Horn, politician (born 1664)
• - Lars Roberg, physician (born 1664)
• June 21 - Johannes Steuchius, arch bishop (born 1676)