Anathon August Fredrik Aall (15 August 1867 – 9 January 1943) was a Norwegian academic. Originally educated as a theologian, he was rejected for a professorship in this field, and switched to philosophy and psychology. He ultimately became a professor of philosophy at University of Oslo.
He was born in Nesseby, Finnmark as a son of vicar Niels Anton Aall (1833–1896) and his wife Mathilde Susanne Dahl (1842–1910). He was the brother of jurist and Fascist politician Herman Harris Aall, and a grandson of Hans Cato Aall. He was also a great-great-great-grandson of Nicolai Benjamin Aall, and a great-great-grandnephew of Niels, Jørgen and Jacob Aall.
From 1899 he was married to Cathrine Antonie Langaard, a daughter of businessman Conrad Langaard. She died in 1926. In October 1928 he married Austrian citizen Lily Weiser (1898–1987), an ethnologist; she took the name Lily Weiser Aall. Also, his sister Marna was married to philosopher Kristian Birch-Reichenwald Aars from 1895 to 1910. Anathon Aall biographed Aars in the first volume of the first edition of the biographical dictionary Norsk biografisk leksikon.
Anathon Aall was the grandfather of Norwegian psychologist Lisbeth F.K. Holter Brudal.
Aall's family moved a lot during his early years, since his father was a priest. Aall finished his secondary education in Stavanger in 1886, and graduated from the Royal Frederick University with the degree cand.theol. in 1892. From 1893 to 1897 he undertook religious studies in four European countries. In 1897 he applied for a position as professor of church history at the Royal Frederick University, but he was rejected as the assessment committee found that he was "deviating from the faith of our Church", and hence was "unfit" to lecture for priestly candidates.