Erik Tullius Hammargren (18 October 1814 – 14 February 1899) was a Swedish Lutheran priest, ornithologist, and textbook writer.

Hammagren became a student in Lund in 1832 and obtained a master's degree in philosophy in 1838.

He enrolled in the medical faculty at Uppsala University in 1840.

[1] Hammargren worked as a teacher at a school in Åmål, Dalsland from 1837 to 1852.

In 1875, the celebrated Swedish author and Nobel Prize laureate, Selma Lagerlöf, resided with him, alongside his spouse, Ottiliana Lagerlöf, who happened to be her aunt at the Karlskoga Church Rectory.