Pierre Allorge (12 April 1891 – 21 January 1944) was a French botanist born in Paris.
He studied natural sciences in Paris, obtaining his doctorate with a thesis titled Les Associations végétales du Vexin français.
In 1937 he was appointed president of the Société botanique de France.
[1] Together with his wife Valentine Allorge he issued several series of bryophyte exsiccatae in the time span between 1928 and 1949.
[2] In 1924 he founded the journal Revue algologique with Gontran Hamel (1883–1944).