Theodor Wisén (31 March 1835 – 15 February 1892) was a Swedish philologist of Scandinavian languages.

Wisén was born in the parish of Vissefjärda in Kalmar County.

He studied the classics, especially Greek, before turning to Scandinavian languages.

He was appointed professor in Lund in 1865, a position he held until his death.

His edition of the Homiliu-bok was awarded the prize by the Swedish Academy in 1874, and he published a number of notable books and monographs on Icelandic poetry.