Thomas Johannessen Heftye, also known as Tho Joh Heftye (29 October 1822 – 4 October 1886) was a Norwegian businessman, politician and philanthropist.
He was born in Christiania as the son of merchant Johannes Thomassen Heftye (1792–1856) Tina Haslef (1798–1862). He was a nephew of Henrik Heftye.
In October 1846 he married Marie Jacobine Meyer (1826–1895), a daughter of Jacob Peter Meyer and sister of Thorvald Meyer. Their son Thomas Heftye became a notable politician. Through his daughter Ingeborg Marie he was a father-in-law of Frits Hansen and grandfather of Eilif Fougner.
His grandfather migrated to Norway from Switzerland in the late eighteenth century, and founded the family company Thos. Joh. Heftye & Søn. Heftye grew up at Filipstad. He took his secondary education at Oslo Cathedral School and his higher education mainly in Leipzig. He entered the family company in 1848.
Heftye was heavily involved in the organizational life of the time. He co-founded the Norwegian Trekking Association in 1868. He owned the rural areas Sarabråten, Frognerseteren and Tryvannshøyden. Already in his lifetime these were opened as recreational areas; the two latter areas later became publicly owned. He was also a member of the board of Akers Sparebank from 1873 to his death, and also of Norges Forsvarsforening, Christiania Theatre, the Society for the Preservation of Ancient Norwegian Monuments and Christiania Kunstforening. He was a known patron of the arts, and financed the publication of the diaries of Claus Pavels. He also financed writers and artists such as Aasmund Olavson Vinje, Bjørnstjerne Bjørnson, Hans Gude and P. A. Munch.