Wilhelm Ostwald (September 2, 1853 - April 3, 1932) was a German chemist.

He was born in Riga (at that time Russia, today Latvia), as the son of master-cooper Gottfried Wilhelm Ostwald and Elisabeth Leuckel.

He invented the Ostwald process used in the manufacture of nitric acid, leading to mass production of fertilizers and explosives. He also did significant work on dilution theory leading to his discovery of the law of dilution which is named after him.

He received the Nobel prize for Chemistry in 1909 for his work on catalysis, chemical equilibria and reaction velocities.

After an extremely active life, Ostwald died at his country home near Leipzig.