Avraham Fahn (Hebrew:אברהם פאהן born 8 August 1916,[1] died 19 February 2012)[2] was an Israeli professor of botany at the Hebrew University of Jerusalem.

He emigrated to Mandate Palestine and studied at the Hebrew University of Jerusalem, receiving a PhD in 1948.

Following the Six Days War in 1967, Fahn assisted in the restoration of the botanical gardens at the University's Mount Scopus campus.

He also served for many years as head of the Forestry Department of the Volcani Institute of Agricultural Research.

His books on the anatomy of plants have become basic texts in the field of botany.