Robert Heinrich Friedrich Denzler (19 March 1892 – 25 August 1972) was a Swiss composer and conductor.
He studied with Fritz Niggli (piano) as well as with William Ackroyd and with Willem de Boer (violin) at the Zurich University of the Arts.
He also received private lessons in theory and composition from Volkmar Andreae, principal conductor of the Tonhalle Orchester Zürich.
During the summer months, he also worked as a musical assistant at the Bayreuth Festival under the conductors Hans Richter, Karl Muck and Michael Balling and as répétiteur at the Cologne Stadttheater.
He brought Alban Berg's Lulu in 1937 and Paul Hindemith's opera Mathis der Maler to the premiere in 1938.
In 1959, he was awarded the Hans-Georg-Nägeli-Medal of the city of Zurich (on the occasion of the world premiere of his Romantic Symphony).