Johann Heinrich Friedrich Link (2 February 1767 – 1 January 1851) was a German naturalist and botanist.
Link was born at Hildesheim as a son of the minister August Heinrich Link (1738–1783), who taught him love of nature through collection of 'natural objects'. He studied medicine and natural sciences at the Hannoverschen Landesuniversität of Göttingen, and graduated as MD in 1789, promoting on his thesis "Flora der Felsgesteine rund um Göttingen" (Flora of the rocky beds around Göttingen). One of teachers was the famous natural scientist Johann Friedrich Blumenbach (1752–1840). He became a private tutor (Privatdozent) in Göttingen.
In 1792 he became the first professor of the new department of chemistry, zoology and botany at the . During his stay at Rostock, he became an early follower of the antiphlogistic theory of Lavoisier, teaching about the existence of oxygen instead of phlogiston. He was also a proponent of the attempts of Richter to involve mathematics in chemistry, introducing stoichiometry in his chemistry lessons. In 1806 he set up the first chemical laboratory at Rostock in the "Seminargebäude". He began to write an abundant number of articles and books on the most different subjects, such as physics and chemistry, geology and mineralogy, botany and zoology, natural philosophy and ethics, prehistoric and early history. He was twice elected rector of the university.
In 1793 he married Charlotte Juliane Josephi (1768?–1829), sister of his colleague at the university Prof. Wilhelm Josephi (1763–1845).
During 1797–1799 he visited Portugal with Count Johann Centurius Hoffmannsegg, a botanist, entomologist and ornithologist from Dresden. This trip made him finally choose botany as his main scientific calling.