The year 1566 in science and technology included many events, some of which are listed here.

• Rembert Dodoens publishes Frumentorum, leguminum, palustrium et aquatilium herbarum, ac eorum quae eo pertinent historia at Antwerp.

• 1566–67 – Completion of "Stari Most" bridge crossing the Neretva at Mostar by the Ottoman Empire (builder: Mimar Hayruddin).
• Autumn – Probable completion of the Exeter Canal, the first in England, and with the first use of a pound lock in England (engineer: John Trew of Glamorgan).^[1][2]

• Pedro Nunes' work on navigation, Petri Nonii Salaciensis Opera, is published.

• December 29 – Danish astronomer Tycho Brahe, while studying at the University of Rostock in Mecklenburg, loses part of his nose in a duel with fellow nobleman and relation Manderup Parsberg over a mathematical formula.^[3][4]

• Giuseppe Biancani, Italian astronomer (died 1624)
• Jan Jesenius, Slovak physician (died 1621)
• Michal Sedziwój, Polish alchemist (died 1636)
• Caterina Vitale, Maltese pharmacist (died 1619)

• May 4 – Luca Ghini, Italian physician and botanist (born 1490)
• May 10 – Leonhart Fuchs, German botanist (born 1501)
• July 2 – Nostradamus, French physician and astrologer (born 1503)
• July 30 – Guillaume Rondelet, French physician (born 1507)