Ernst Behm (January 4, 1830 – March 15, 1884) was a German geographer and statistician who was a native of Gotha.
Behm studied medicine and sciences at the Universities of Jena, Berlin and Würzburg, and in 1856 began work as an editor at Petermanns Geographischen Mitteilungen in Gotha. This publication was a German language journal of geography founded by August Heinrich Petermann.
In 1866 he became editor of Geographische Jahrbuch (Geographic Annals), and in 1872 with Hermann Wagner (1840–1929) founded the geographical/statistical review, Die Bevölkerung der Erde. Starting in 1876 he headed the editorial staff of the statistical section of the Gothaischen Hofkalenders, and in 1878 following the death of Petermann, he became editor of Petermanns Geographischen Mitteilungen.
In 1872 Behm published an article (Beweise für die Identität des Lualaba mit dem Congo), which scientifically demonstrated that the Lualaba was a headstream of the Congo River. This claim was later confirmed as factual by explorer Henry Morton Stanley in 1877.