The year 1738 in science and technology involved some significant events.

• Pierre Louis Maupertuis publishes Sur la figure de la terre, which confirms Newton's view that the Earth is an oblate spheroid slightly flattened at the poles.

• Publication of Hortus Cliffortianus, a detailed description by Linnaeus of George Clifford's gardens at Hartekamp, Netherlands, including the raising of exotic plants such as bananas in a greenhouse.
• Publication of Rariorum Africanarum plantarum, a flora of Cape Colony by Johannes Burman, begins publication in Amsterdam.

• Abraham de Moivre publishes the second English edition of his The Doctrine of Chances containing a study of the coefficients in the binomial expansion of (a + b)ⁿ.

• February – Great Plague of 1738, an outbreak of bubonic plague, begins to spread from Banat across central Europe.^[1]
• Establishment of The Mineral Water Hospital in Bath, England.

• July 1 – William Champion of Bristol patents a process to distill zinc from calamine using charcoal in a smelter.^[2]

• June 24 – Lewis Paul and John Wyatt obtain a British patent for roller cotton-spinning machinery.
• Jacques de Vaucanson presents the world's first automaton, The Flute Player (1737) to the French Academy of Sciences.
• Black Forest clockmaker Franz Ketterer produces one of the earliest cuckoo clocks.

• Copley Medal: James Valoue^[3]

• November 15 – William Herschel, German-born astronomer (died 1822)

• June 21 – Charles Townshend, 2nd Viscount Townshend, English agriculturalist (born 1674)
• September 23 – Herman Boerhaave, Dutch physician (born 1668)