Paul Pfeiffer (21 April 1875 – 4 March 1951) was an influential German chemist.
He received his Ph.D.
at the University of Zurich, studying under Alfred Werner, the "father of coordination chemistry".
His thesis, submitted in 1898, dealt with adducts of tin halides.
Pfeiffer was considered Werner's most successful student and became Werner's assistant until, due to a dispute with his mentor, he left first for Rostock, then Karlsruhe, and finally Bonn.