Herman Ernst Henrik Gesellius (16 January 1874 – 24 March 1916) was a Finnish architect.

[1] In 1896 he founded the architecture firm Gesellius, Lindgren, Saarinen with Armas Lindgren and Eliel Saarinen.

[2][3][4] The most famous work projected under his own name is the Wuorio House ("Wuorion talo") at Unioninkatu 30, Helsinki.

It also features sculptures by Felix Nylund [fi].

[2] Gesellius withdrew from architectural work in 1912 because of a serious illness.