Theodor Heinrich Hermann von Heldreich (3 March 1822 – 7 September 1902) was a German botanist born in Dresden.

[1] Scion of an old aristocratic family, he was the son of Conrad Friedrich Robert Heldreich and Amalia Charlotte Humbold.

In 1841, he was honoured by botanist Pierre Edmond Boissier, who named a genus of plants (in family Brassicaceae) from Palestine and Turkey Heldreichia.

[2][3] His first botanical expedition was to Sicily, after which he published his first work "Tre nuove specie di piante scoverte nella Sicilia".

It was during this period, in 1862 in Athens, Heldreich met John Stuart Mill who was travelling through Greece with his stepdaughter, Helen Taylor (feminist), collecting specimens of the Greek flora.

Their meeting is documented in John Stuart Mill's botanical notebooks lodged in the Archives of the London School of Economics.

In 1855 Theodor von Heldreich married Sofia, daughter of I. Katakouzinos and granddaughter of Greek scholar and patriot, Konstantinos Koumas.