17 March – The Dutch general elections for the House of Representatives of the Netherlands are scheduled to take place.
23 March – The Israeli general elections are scheduled to take place, the fourth Knesset election in 2 years.
4 April – Bulgaria will hold parliamentary elections.
19 April – Raúl Castro will resign as First Secretary of the Cuban Communist Party, ending 62 years of rule by the Castro brothers in Cuba.
25 April – Albania will hold parliamentary elections
27 April – 6 June – Israel is scheduled to hold a presidential election.
18 May – 22 May – The Eurovision Song Contest 2021 is scheduled to be held in Rotterdam, Netherlands, after the cancellation of the 2020 contest due to the COVID-19 pandemic.
26 May – The second-shortest total lunar eclipse of the 21st century will occur, lasting just 14 minutes and 30 seconds.
3 June – 6 June – The 2020 CONCACAF Nations League Finals is scheduled to be held in the United States. They were rescheduled from 4–7 June 2020, due to the COVID-19 pandemic.
10 June – Annular solar eclipse.
11 June – 11 July – The UEFA Euro 2020 is scheduled to be held across Europe, and the 2021 Copa América to be held in Argentina and Colombia. Both competitions were rescheduled from 12 June 2020 due to the COVID-19 pandemic.
23 July – 8 August – The 2020 Summer Olympics are scheduled to be held in Tokyo, Japan. They were rescheduled from 24 July 2020, due to the COVID-19 pandemic.
5 September – The Hong Kong Special Administration Region in China is scheduled to hold an election for the Legislative Council.
13 September – Norway plans to hold a parliamentary election, with all seats in the Storting up for election.
26 September – Germany is scheduled to hold the federal election for the Bundestag on this date.
1 October – The 2020 World Expo is scheduled to begin. Its opening was rescheduled from 20 October 2020 due to the COVID-19 pandemic.
6 October – 10 October – The 2021 UEFA Nations League Finals is scheduled to be held in Italy. They were originally scheduled for 2–6 June 2021, but were moved to 6–10 October 2021 following the rescheduling of UEFA Euro 2020 to June and July 2021 due to the COVID-19 pandemic.
22 October – Japan is scheduled to hold a general election for the House of Representatives.
23 October – 27 November – The 2021 Rugby League World Cup is scheduled to take place in England.
31 October – NASA, the ESA, the Canadian Space Agency, and the Space Telescope Science Institute plan to launch the James Webb Space Telescope, a successor to the Hubble Space Telescope.
November – Planned launch of NASA’s Artemis 1 mission to the Moon, the first integrated flight of the agency’s Orion MPCV and Space Launch System (SLS) rocket.
1 November – 12 November – The 2021 UN Climate Change Conference is scheduled to take place in Glasgow, Scotland, United Kingdom. It was rescheduled from 9 November 2020 due to the COVID-19 pandemic.