January 4 – NASA announces the selection of two new Discovery Program space exploration missions: Lucy, a mission to several Jupiter trojan asteroids, and Psyche, a mission to the asteroid 16 Psyche
January 5 – United States defeats Canada to win the gold medal at the 2017 World Junior Ice Hockey Championships.
January 10 – The FIFA Council unanimously approves expansion of the World Cup from 32 to 48 teams starting in 2026.
January 11 – Norway becomes the first country to start a complete switch-off of national FM radio stations.
January 17 – Antonio Tajani has been elected as new President of the European Parliament.
January 18 – Global temperatures rose to the hottest level on record for 2016 for a 3rd successive record according to NASA and the US National Oceanic and Atmospheric Administration.
January 20 – Donald Trump is sworn in as the 45th President of the United States.
January 22 – The Indian state government of Tamil Nadu lifts its ban on the sport of Jallikattu.
January 25 – With a victory in the 2nd stage of the Vuelta a San Juan, Tom Boonen becomes the first professional road cyclist to win a race on a bike equipped with disc brakes.
January 25 – In sumo wrestling, Kisenosato Yutaka becomes the 72nd yokozuna.
January 28 – Executive Order 13769: Travelers from Iran, Iraq, Libya, Somalia, Sudan, Syria, and Yemen are blocked from entering the United States. January 28 – 2017 Australian Open: Serena Williams defeats Venus Williams to win the women's singles and an Open era-record 23rd Grand Slam singles title.
January 29 – 2017 Australian Open: Roger Federer of Switzerland defeats Rafael Nadal of Spain in the final of the men's singles.
January 29 – 2017 Bandy World Championship: The World Championship Division A starts, Sweden defeats Finland 8-2.
January 29 – Winter X Games Aspen '17: The United States won 22 medals, including seven gold medals. Canada was 2nd with two golds, nine overall.
January 30 – Gambian President Adama Barrow removes "Islamic" from the country's official name. The Gambia will now officially be called The Republic of The Gambia.
January 31 – Morocco rejoins the African Union after a 33-year absence, despite opposition from several member states over the political status of Western Sahara.
January 31 – Susan Kiefel is sworn in as the first female Chief Justice of Australia.
February 12 – Former Foreign Minister Frank-Walter Steinmeier is elected President of Germany.
February 15 – The Indian Space Research Organisation (ISRO) launches a record 104 satellites in single mission.
February 18 – Iran defeats the US to take the gold medal in freestyle wrestling's World Cup.
February 22 – NASA and the European Southern Observatory announce the discovery of four new Earth-like planets in the Goldilocks zone of the star TRAPPIST-1, in addition to the three discovered there last year.
March 6 – U.S. President Donald Trump signs a revised version of Executive Order 13769 eliminating Iraq from the order.
March 17 – French mathematician Yves Meyer wins the Abel Prize for his work on the mathematical theory of wavelets.
March 20 – British Prime Minister Theresa May announces that her government will trigger article 50, which begins the process of withdrawing from the European Union, on March 29
April 4 – English computer scientist Sir Timothy John Berners-Lee is awarded the 2016 A.M. Turing Award for inventing the World Wide Web.
April 13 – NASA announces Saturn's moon Enceladus has the conditions in its global subsurface ocean to support life.
April 20 – China launches its 1st cargo spacecraft, the Tianzhou 1, carried by a Long March 7 rocket.
April 24 – Peggy Whitson, commander of the International Space Station (ISS), breaks the record for most total days spent in space by any NASA astronaut, at more than 534 days.
April 28 – Ilir Meta is elected the new President of Albania, winning 87 votes out of 140 members of the Assembly.
May 5 – ISRO has successfully launched a new communications satellite for South Asia from Satish Dhawan Space Centre, India.
May 5 – The Comac C919 makes its maiden flight from Shanghai Pudong International Airport, China.
May 9 – South Koreans vote in a presidential election, with Moon Jae-in of the Democratic Party of Korea winning the election.
May 14 – The Government of China begins a two-day summit in Beijing, in an attempt to raise international support for its Belt and Road Initiative.
May 14 – France swears in Emmanuel Macron as the 25th President of France.
May 20 – Incumbent President Hassan Rouhani is re-elected, defeating Ebrahim Raisi.
May 23 – Scientists discover 7.2 million-year-old "pre-human" remains in the Balkans area near Bulgaria and Greece.
June 5 – Apple announces iOS 11 in WWDC 2017.
June 6 – Uzbekistan Deputy Prime Minister Rustam Azimov is dismissed by President Shavkat Mirziyoyev.
June 11 – Rafael Nadal defeats Stan Wawrinka of Switzerland, to win the men's singles at the French Open. It is Nadal's 10th win in the French Open.
June 12 – In association football, Iran becomes the 2nd team to qualify for the 2018 FIFA World Cup after Brazil, and the 1st Asian side, by defeating Uzbekistan.
June 14 – The Egyptian parliament approves the transfer of two uninhabited Red Sea islands, Tiran Island and Sanafir Island, to Saudi Arabia.
June 18 – In cricket, Pakistan wins the 2017 ICC Champions Trophy Final defeating India by 180 runs.
June 22 – In cricket, the International Cricket Council votes to elevate Afghanistan and Ireland to full Test status. The two countries become the 11th and 12th Test nations.
June 25 – In basketball, Spain defeats France 71–55 in the final to win the EuroBasket Women 2017.
June 26 – Chinese political activist and Nobel Peace Prize laureate Liu Xiaobo is released from prison on medical parole.
July 6 – Scientists announce the detection of a new subatomic particle at the Large Hadron Collider.
July 16 – Roger Federer defeats Marin Čilić of Croatia to win the men's singles tournament. Federer wins his 8th Wimbledon singles title, surpassing William Renshaw and Pete Sampras for the most by a male player
July 31 – Los Angeles has reportedly reached an agreement with the International Olympic Committee to host the 2028 Games.
August 5 – Iranian President Hassan Rouhani takes the oath of office to start his second four-year term.
August 5 – Venkaiah Naidu elected as India's 13th Vice-President of India.
August 14 – LIGO and Virgo observatories detect the gravitational wave signal from two merging black holes.
September 13 – The International Olympic Committee awards the 2024 Summer Olympics to Paris and the 2028 Summer Olympics to Los Angeles.
September 17 – The fifth Asian Indoor Games open in Ashgabat, Turkmenistan, with around 5,500 athletes from 61 countries participating in the event which will last until September 27.
September 19 – The 72nd session of the United Nations General Assembly commences its General Debate at the United Nations headquarters in Manhattan, New York.
October 2 – The Nobel Prize committee awards Americans Jeffrey C. Hall, Michael Rosbash, and Michael W. Young the prize for their work on molecular mechanisms that control circadian systems.
October 3 – The Nobel Prize committee awards Americans Rainer Weiss, Barry Barish, and Kip Thorne the Nobel Prize in Physics for their work in the LIGO Scientific Collaboration that discovered gravitational waves.
October 4 – The Nobel Committee awards Swiss Jacques Dubochet, German Joachim Frank, and British Richard Henderson the Nobel Prize in Chemistry for developing cryo-electron microscopy.
October 5 – The Nobel Committee awards Japanese-born British novelist Kazuo Ishiguro the Nobel Prize in Literature for his "novels of great emotional force.
October 6 – The Nobel Committee awards the global civil society coalition of The International Campaign to Abolish Nuclear Weapons the Nobel Peace Prize
October 9 – Iceland qualifies for the 2018 FIFA World Cup after defeating Kosovo 2–0 to win UEFA Group I.
October 27 – Catalonia declares independence from Spain.
November 2 – The Tapanuli orangutan is identified as a new species of great ape.
November 5 – The German newspaper Süddeutsche Zeitung publishes 13.4 million documents leaked from the offshore law firm Appleby.
November 20 – U.S. President Donald Trump announces the designation of North Korea as a state sponsor of terrorism.
November 21 – Robert Mugabe resigns as the President of Zimbabwe shortly after impeachment proceedings are launched. It ends a period of his 29 years in office as President.
December 1 – The draw for the 2018 FIFA World Cup takes place at the State Kremlin Palace in Moscow, Russia.
December 5 – A 14-person International Olympic Committee panel bans Russia from the Winter Olympics in PyeongChang, South Korea, after a report finds evidence of systemic doping cheating in the 2014 Winter Olympics.
December 6 – The United States officially recognises Jerusalem as Israel's capital.
December 21 – UN votes 128-9 to reject US decision on Jerusalem.
December 22 – The UN Security Council votes 15–0 in favor of additional sanctions on North Korea, including measures to slash the country's petroleum imports by up to 90%.