Lazarus Geiger (21 May 1829 – 29 August 1870) was a German Jewish philosopher and philologist.
He was born at Frankfurt-on-Main, was destined to commerce, but soon gave himself up to scholarship and studied at Marburg, Bonn and Heidelberg. From 1861 till his sudden death in 1870 he was professor in the Jewish high school at Frankfurt. His chief aim was to prove that the evolution of human reason is closely bound up with that of language. He further maintained that the origin of the Indo-Germanic language is to be sought not in Asia but in central (Germany). He was a convinced opponent of rationalism in religion.
It was Lazarus Geiger, ... who first detected universal sequence in the acquisition of basic colour terms.