Philibert Jacques Melotte (29 January 1880 – 30 March 1961) was a British astronomer whose parents emigrated from Belgium.
In 1908 he discovered a moon of Jupiter, today known as Pasiphaë. It was simply designated "Jupiter VIII" and was not given its present name until 1975. The outer main-belt asteroid 676 Melitta, the only asteroid he discovered, is named after the Attic form of the Greek Melissa, the bee, but its resemblance to the discoverer's name is not fortuitous.
The conspicuous star cluster in the Coma Berenices constellation is commonly designated Mel 111 since it appeared in Melotte's 1915 catalogue of star cluster but not in Charles Messier's famous catalogue of deep sky objects or in the New General Catalogue since it was not proved to be a true cluster until 1938 by the astronomer R J Trumpler.
Melotte was awarded the Jackson-Gwilt Medal of the Royal Astronomical Society in 1909.