The year 1854 in science and technology involved some significant events, listed below.

• July 22 – Discovery of the asteroid 30 Urania by John Russell Hind.
• October c. – George Airy calculates the mean density of the Earth by measuring the gravity in a coal mine in South Shields.

• Benjamin Silliman of Yale University is the first person to fractionate petroleum into its individual components by distillation.

• January 4 – First definite sighting of McDonald Islands in the Antarctic.

• March 26 – Playfair cipher first demonstrated, by Charles Wheatstone.
• George Boole's work on algebraic logic, An Investigation of the Laws of Thought on Which are Founded the Mathematical Theories of Logic and Probabilities, published in London.^[1]
• Arthur Cayley states the original version of Cayley's theorem and produces the first Cayley table.^[2][3]
• Bernhard Riemann, a German mathematician, submits his habilitation thesis Ueber die Darstellbarkeit einer Function durch eine trigonometrische Reihe ("About the representability of a function by a trigonometric series"), in which he describes the Riemann integral. It is published by Richard Dedekind in 1867.^[4]

• April–May – Dr John Snow traces the source of one outbreak of cholera in London (which kills 500) to a single water pump, validating his theory that cholera is water-borne, and forming the starting point for epidemiology.
• November – Florence Nightingale and her team of trained volunteer nurses arrive at Selimiye Barracks in Scutari in the Ottoman Empire to care for British Army troops invalided from the Crimean War.^[5]
• Spanish-born vocal pedagogist Manuel García observes his own functioning glottis using a form of laryngoscope incorporating mirrors.^[6][7]
• Claude Bernard introduces the term Milieu intérieur in physiology.

• Filippo Pacini, an Italian anatomist, discovers Vibrio cholerae, the bacterium that causes cholera.^[8]
• Louis Pasteur begins studying fermentation at the request of brewers.

• May 9 – Albert Fink patents the Fink truss in the United States.^[9]
• May 17 – Deck of Wheeling Suspension Bridge in the United States destroyed through torsional movement and vertical undulations in a severe windstorm.
• June 13 – Anthony Faas patents improvements to the accordion in the United States.^[10]
• July – First voyage by a seagoing steamship fitted with a compound steam engine, the screw steamer Brandon, built on the River Clyde in Scotland by John Elder.^[11]
• September 19 – Thaddeus Hyatt patents a practical pavement light.^[12]
• November 27 – André-Adolphe-Eugène Disdéri patents a method of producing carte de visite photographs in France.
• December 20 – In the case of Talbot v. Laroche, pioneer of photography Henry Fox Talbot fails in asserting that the collodion process infringes his calotype patent.^[13]
• James Ambrose Cutting takes out three United States patents for improvements to the wet plate collodion process (Ambrotype photography).
• Elisha Otis completes work on the safety elevator.

• 10 June – The Crystal Palace reopens in Sydenham, South London^[14] with life-size dinosaur models in the grounds.

• Copley Medal: Johannes Peter Müller^[15]
• Wollaston Medal for Geology: Richard John Griffith

• January 27 – George Alexander Gibson (died 1913), Scottish physician and geologist.
• January 29 – Fred Baker (died 1938), American physician and naturalist.
• February 9 – Aletta Jacobs (died 1929), Dutch physician and women's suffrage activist.
• March 4 – Napier Shaw (died 1945), English meteorologist.
• March 15 – Emil Adolf von Behring (died 1917), German physiologist, winner of the Nobel Prize in Physiology or Medicine in 1901.
• March 31 – Dugald Clerk (died 1932), Scottish mechanical engineer.
• April 28 – Phoebe Marks, later Hertha Ayrton (died 1923), English electrical engineer.^[16]
• April 29 – Henri Poincaré (died 1912), French mathematician.
• May 11 – Ottmar Mergenthaler (died 1899), German-born inventor.
• June 13 – Charles Algernon Parsons (died 1931), British inventor of the steam turbine.
• July 12 – George Eastman (suicide 1932), American photographic inventor.
• July 23 – Birt Acres (died 1918), American-born cinematographic inventor.
• July 28 – Victor Babeș (died 1926), Austrian-born Romanian physician and bacteriologist.
• October 3 – Hermann Struve (died 1920), Russian-born astronomer.

• January 16 – Charles Gaudichaud-Beaupré (born 1789), French botanist.
• April 15 – Arthur Aikin (born 1773), English chemist and mineralogist.
• July 6 – Georg Ohm (born 1789), German physicist.
• September 28 – George Field (born c.1777), English colour chemist.
• October 27 – Golding Bird (born 1814), English physician.
• November 18 – Edward Forbes (born 1815), Manx naturalist.