The year 1841 in science and technology involved some significant events, listed below.

• Rev. Miles Joseph Berkeley demonstrates that Phytophthora infestans (potato blight) is a fungal infection.
• Royal Botanic Gardens, Kew, first open to the public^[1] and William Hooker appointed director.
• John Gould begins publication of A Monograph of the Macropodidae, or Family of Kangaroos.

• Theobromine is first discovered in cacao beans by Russian chemist Alexander Woskresensky.^[2][3]
• Uranium is first isolated, by Eugène-Melchior Péligot.
• Chemical Society of London founded by Thomas Graham.
• Reinsch test for heavy metals discovered by Hugo Reinsch.^[4]

• January 27 – The active volcano Mount Erebus in Antarctica is discovered and named by James Clark Ross.^[5]
• January 28 – Ross discovers the "Victoria Barrier", later known as the Ross Ice Shelf.
• Ross additionally discovers the Ross Sea, Victoria Land and Mount Terror.

• Hugh Miller publishes The Old Red Sandstone.
• The first comprehensive geological map of France is published by Dufrénoy and Élie de Beaumont, the result of thirteen years of investigations.

• November 13 – Scottish surgeon James Braid attends his first demonstration of animal magnetism (given by Charles Lafontaine in Manchester, England) which leads to Braid's study of the subject he eventually calls hypnotism.

• Prussian mathematician Karl Weierstrass discovers but does not publish the Laurent expansion theorem.
• English mathematician William Rutherford calculates an approximation of π to 208 decimal places of which the first 152 are correct.

• Platelets are first described from microscopic observation by George Gulliver.

• February – H. Fox Talbot obtains a patent in the United Kingdom for the calotype process in photography.^[6]
• April 16 – Loring Coes patents the screw type wrench commonly known as the monkey wrench in the United States.
• April 24 – Squire Whipple patents the iron bowstring arch through truss bridge in the United States.^[7]
• Draughtsman William Howe and pattern-maker William Williams of Robert Stephenson and Company in Newcastle upon Tyne originate Stephenson valve gear for the steam locomotive.
• Joseph Whitworth introduces the British Standard Whitworth system of screw threads in his paper On a Uniform System of Screw Threads.
• American artist John G. Rand invents the collapsible zinc oil paint tube, marketed by Winsor & Newton of London.^[8]

• Copley Medal: Georg Ohm^[9]
• Wollaston Medal: Adolphe Theodore Brongniart

• January 29 – Henry Morton Stanley (died 1904), explorer, journalist.
• February 2 – François-Alphonse Forel (died 1912), pioneer in the study of lakes.
• February 4 – Clément Ader (died 1926), engineer and inventor, airplane pioneer.
• February 24 – Carl Gräbe, (died 1927) chemist.
• March 6 – Alfred Cornu (died 1902), physicist.
• August 4 – W. H. Hudson (died 1922), naturalist.
• August 25 – Emil Theodor Kocher (died 1917), 1909 winner of the Nobel Prize in Physiology or Medicine
• October 12 – Joseph O'Dwyer (died 1898), physician
• October 26 – Theodor von Oppolzer (died 1886), astronomer.
• November 3 – Eugen Warming (died 1924), botanist and founder of ecology.
• December 29 – Rosalie Fougelberg (d. 1911), Swedish dentist

• April 22 – Charles Barbier, inventor of a method of writing for the blind that was the inspiration for Braille.
• May 16 – Marie Boivin, French midwife, inventor and obstetrics writer (born 1773)
• May 31 – George Green (born 1793), English mathematician.
• August 18 – Louis de Freycinet (born 1779), explored coastal regions of Western Australia.
• September 9 – Augustin Pyramus de Candolle (born 1778), Swiss botanist.
• October 28 – Johan August Arfwedson (born 1792), Swedish chemist.