The following events in science and technology occurred in the year 1918.

• June 8 – Nova Aquila, the brightest observed since 1604, is discovered.
• Kiyotsugu Hirayama identifies several groups of main belt asteroids, now known as Hirayama families.
• Harlow Shapley demonstrates that globular clusters are arranged in a spheroid or halo whose center is not the Earth, but the center of the galaxy.
• Heber Curtis discovers a relativistic jet of matter emerging from Elliptical galaxy M87.

• February 21 – The last known Carolina parakeet (the only parrot species native to the eastern United States) dies in Cincinnati Zoo.
• Around 1000 pilot whales strand in the Chatham Islands.
• R. A. Fisher puts forward a genetic model that shows that continuous variation could be the result of Mendelian inheritance in his paper "The Correlation Between Relatives on the Supposition of Mendelian Inheritance".
• J. Henri Fabre's The Sacred Beetle, and others published in English.^[1]
• Jacques Loeb's Forced Movements, Tropisms, and Animal Conduct published in the United States.^[2]

• February 23 – Arthur Scherbius applies to patent the Enigma machine.^[3]
• Edward Hugh Hebern patents the Hebern rotor machine.

• Technisches Museum Wien opens in Vienna.

• Felix Hausdorff introduces the concept of the fractional Hausdorff dimension.^[4]
• Gaston Julia describes the iteration of a rational function.^[5]

• July 26 – Emmy Noether introduces what becomes known as Noether's theorem, from which conservation laws are deduced for symmetries of angular momentum, linear momentum and energy, at Göttingen, Germany.
• Josef Lense and Hans Thirring find the gravitomagnetic precession of gyroscopes in the equations of general relativity.
• Hans Reissner and Gunnar Nordström solve the Einstein and Maxwell field equations for charged spherically symmetric non-rotating systems.
• Friedrich Kottler gets a Schwarzschild solution without Einstein vacuum field equations.

• January – 1918 flu pandemic: "Spanish 'flu" (influenza) first observed in Haskell County, Kansas.^[6]
• March 26 – Dr. Marie Stopes publishes her influential book Married Love in the U.K., following it with Wise Parenthood, a treatise on birth control.
• June–August – "Spanish 'flu" becomes pandemic.^[7]
• September 7 – J. B. Christopherson publishes his discovery that antimony potassium tartrate is an effective cure for bilharzia.^[8]
• Hartog Jacob Hamburger describes the chloride shift.^[9]

• April 10 – Alexander M. Nicholson files a United States patent for the radio crystal oscillator.^[10]
• July – American cinematographer Frank D. Williams is granted a patent for the "Williams process" of travelling matte.^[11]
• Edwin Howard Armstrong develops the superheterodyne receiver.^[12]
• George Constantinescu publishes Theory of sonics: a treatise on transmission of power by vibrations,^[13] originating the study of this branch of continuum mechanics.
• Theodore von Karman and Asbóth Oszkár build the first co-axial helicopter.
• Charles Strite invents the pop-up toaster.^[14]

• Nobel Prize
  • Physics – Max Karl Ernst Ludwig Planck
  • Chemistry – Fritz Haber^[15]
  • Medicine – not awarded

• January 23 – Gertrude B. Elion (died 1999), American pharmacologist, Nobel laureate.
• January 27 – Antonín Mrkos (died 1996), Czech astronomer.
• March 13 – Marjorie Blamey (died 2019), English botanical illustrator.
• March 16 – Frederick Reines (died 1998), American physicist, Nobel laureate.^[16]
• April 4 – Joseph Ashbrook (died 1980), American astronomer.
• April 25 – Gérard de Vaucouleurs (died 1995), French astronomer.
• May 11 – Richard Feynman (died 1988), American physicist, Nobel laureate.
• May 20 – Alexandra Illmer Forsythe (died 1980), American computer scientist
• June 6 – Edwin G. Krebs (died 2009), American biochemist, Nobel laureate.
• July 15
  • Bertram Brockhouse (died 2003), Canadian physicist.
  • Brenda Milner, English-born neuropsychologist.
• July 16 – Samuel Victor Perry (died 2009), English biochemist, pioneer in the field of muscle biochemistry.
• August 3 – Cheng Kaijia (died 2018), Chinese nuclear physicist.
• August 13 – Frederick Sanger (died 2013), English molecular biologist, double Nobel laureate.
• August 26 – Katherine Johnson (died 2020), African American mathematician and space physicist.
• August 29 – John Herivel (died 2011), British cryptanalyst and science historian.
• September 8 – Derek Barton (died 1998), English-born organic chemist, Nobel laureate.
• September 27 – Martin Ryle (died 1984), English radio astronomer.
• October 4 – Adrian Kantrowitz (died 2008), American cardiac surgeon.
• November 10 – Ernst Otto Fischer (died 2007), German chemist, Nobel laureate.
• November 19 – Hendrik C. van de Hulst (died 2000), Dutch astronomer.
• December 25 – Tamara Mikhaylovna Smirnova (died 2001), Russian astronomer.
• Eleanor C. Pressly (died 2003), American mathematician and aeronautical engineer.

• January 6 – Georg Cantor (born 1845), German mathematician.
• January 26 – Ewald Hering (born 1834), German physiologist.
• January 31 – Ivan Puluj (born 1845), Austrian-born Ukrainian physicist.
• April 20 – Karl Ferdinand Braun (born 1850), German physicist, Nobel laureate.
• May 1 – G. K. Gilbert (born 1843), American geologist.
• May 31 – Alexander Mitscherlich (born 1836), German chemist.
• June 13 – Samuel Jean de Pozzi (born 1846), French gynaecologist.
• June 27 – George Mary Searle (born 1839), American astronomer.
• June 29 – Alfred Senier (born 1853), Irish chemist.
• September 7 – Peter Ludwig Mejdell Sylow (born 1832), Norwegian mathematician.
• August 22 – Korbinian Brodmann (born 1868), German neurologist.
• October 28 – Ulisse Dini (born 1845), Italian mathematician.
• November 3 – Aleksandr Lyapunov (born 1857), Russian mathematician and physicist.
• November 29 – Thomas Allinson (born 1858), English physician and dietetic reformer.
• December 26 – William Hampton Patton (born 1853), American entomologist.
• December 27 – Birt Acres (born 1854), American-born English pioneer of cinematography.