The year 1887 in science and technology involved many significant events, listed below.

• April – Carte du Ciel project initiated by Paris Observatory director Amédée Mouchez.
• Theodor von Oppolzer's Canon der Finsternisse, a compilation of the 8,000 solar and 5,200 lunar eclipses from 1200 BC until 2161 AD, is published posthumously.^[1]

• Jean Pierre Mégnin publishes Faune des Tombeaux ("Fauna of the Tombs"), the founding work of modern forensic entomology.^[2]
• Sergei Winogradsky discovers the first known form of lithotrophy during his research with Beggiatoa.^[3]
• The Petri dish is created by German bacteriologist Julius Richard Petri.

• Amphetamine is first synthesized in Germany by Romanian chemist Lazăr Edeleanu, who names it phenylisopropylamine.
• Otto Schott produces 'Normalthermometerglas' (family of Borosilicate glass) for the first time.

• Guyou hemisphere-in-a-square projection developed by Émile Guyou.^[4]

• January 28 – In a snowstorm at Fort Keogh, Montana, in the United States, the largest snowflakes on record are reported. They are 15 inches (38 cm) wide and 8 inches (20 cm) thick.^[5]
• September 28 – Start of the Yellow River floods in China: 900,000 dead.

• June 23 – The Rocky Mountains Park Act becomes law in Canada, creating that nation's first national park, Banff National Park.^[6]

• February 23 – The French Riviera is hit by a large earthquake, killing around 2,000 along the coast of the Mediterranean Sea.
• In Hawaii, the Mauna Loa volcano eruptions subside, having begun in 1843. During the 1887 eruption, about 2½ million tons (2.3 million metric tons) of lava per hour pours out, covering an area of 29 km².

• March 3 – Anne Sullivan begins to teach language to the deaf and blind Helen Keller.
• July 26 – L. L. Zamenhof publishes Lingvo internacia ("International language") under the pseudonym "Doktoro Esperanto".^[7]

• Joseph Louis François Bertrand rediscovers Bertrand's ballot theorem.^[8]
• Henri Poincaré provides a solution to the three-body problem.

• January 11 – Louis Pasteur's anti-rabies treatment is defended in the French Academy of Medicine by Dr. Joseph Grancher.
• August – The U.S. National Institutes of Health is founded at the Marine Hospital, Staten Island, NY, as the Laboratory of Hygiene.
• October 1 – Hong Kong College of Medicine for Chinese founded by Patrick Manson.^[9]
• Franz König publishes "Über freie Körper in den Gelenken" in the journal Deutsche Zeitschrift für Chirurgie, first describing (and naming) the disease Osteochondritis dissecans.
• The Hospitals Association establishes the first (non-statutory and voluntary) register of nurses in the United Kingdom.

• November – The Michelson–Morley experiment is performed, indicating that the speed of light is independent of motion.
• Heinrich Hertz discovers the photoelectric effect on the production and reception of electromagnetic waves in radio, an important step towards the understanding of the quantum nature of light.

• November – G. Stanley Hall founds The American Journal of Psychology.
• Richard Hodgson and S. J. Davey, in the course of investigations into popular belief in parapsychology, publish one of the first descriptions of eyewitness unreliability.^[10]

• March 8 – Everett Horton of Connecticut patents a fishing rod of telescoping steel tubes.
• March 13 – Chester Greenwood patents earmuffs.
• June 8 – Herman Hollerith receives a U.S. patent for his punched card calculator.
• July – James Blyth operates the first working wind turbine at Marykirk in Scotland.^[11][12]
• July 19 – Dorr Eugene Felt receives the first U.S. patent for his comptometer.^[13]
• August – Anna Connelly patents the fire escape.^[14]
• November 8 – Emile Berliner is granted a U.S. patent for his Gramophone.^[15]
• Adolf Gaston Eugen Fick invents the contact lens, made of a type of brown glass.^[16]
• English engineer James Atkinson invents his "Cycle Engine".
• Mexican general Manuel Mondragón patents the Mondragón rifle, the world's first automatic rifle.^[17]
• Alfred Yarrow completes the first practical high-pressure water-tube Yarrow boiler, for a torpedo boat.^[18]

• March 7 – North Carolina State University is established as North Carolina College of Agriculture and Mechanic Arts.
• October 3 – Florida A&M University opens its doors in Tallahassee, Florida.

• Publication in Barcelona of Enrique Gaspar's El anacronópete, the first work of fiction to feature a time machine.^[19]

• June – William Armstrong created 1st Baron Armstrong of Cragside, the first engineer to be raised to the Peerage of the United Kingdom
• Copley Medal: Joseph Dalton Hooker^[20]
• Wollaston Medal for Geology: John Whitaker Hulke

• January 7 – Kurt Schneider (died 1967), German psychiatrist.
• January 15 – Henry Fairfield Osborn, Jr. (died 1969), American conservationist.
• January 28 – Edmund Jaeger (died 1983), American naturalist.
• April 20 – Margaret Newton (died 1971), Canadian plant pathologist.
• June 22 – Julian Huxley (died 1975), English biologist and populariser of science.
• July 30 – Felix Andries Vening Meinesz (died 1966), Dutch geophysicist.
• August 18 – Erwin Schrödinger (died 1961), Austrian physicist.
• September 26 – Barnes Wallis (died 1979), English aeronautical engineer.
• October 11 – María Teresa Ferrari (died 1956), Argentine physician.
• November 10 – Elisa Leonida Zamfirescu (died 1973), Romanian engineer.
• November 19 – James B. Sumner (died 1955), American winner of the 1946 Nobel Prize in Chemistry.
• November 23 – Henry Moseley (killed 1915), English physicist.
• November 25 (November 13 Old Style) – Nikolai Vavilov (died 1943), Russian plant pathologist.
• December 13 – George Pólya (died 1985), Hungarian mathematician.
• December 22 – Srinivasa Ramanujan (died 1920), Indian mathematician.
• December 27 – Edward Andrade (died 1971), English physicist.

• January 22 – Joseph Whitworth (born 1803), English mechanical engineer.
• February 26 – Anandi Gopal Joshi (born 1865), Indian physician.
• July 17 – Henry William Ravenel (born 1814), American botanist.
• July 18 – Dorothea Dix (born 1802), American mental health reformer.
• August 2 – Joseph-Louis Lambot (born 1814), French inventor of ferrocement.
• August 15 – Julius von Haast (born 1824), German geologist.
• August 19
  • Spencer Fullerton Baird (born 1823), American ornithologist and ichthyologist.
  • Alvan Clark (born 1804), American telescope manufacturer.
• October 7 (O.S. September 25) – Lev Tsenkovsky (born 1822), Russian biologist.
• October 17 – Gustav Kirchhoff (born 1824), German physicist.
• November 18 – Gustav Fechner (born 1801), German psychologist.