Mellin is a German surname of the noble Mellin family. Notable people with the surname include:
Albert Mellin, Finnish architect
Charles Mellin (1597–1649), French painter
Hjalmar Mellin (1854–1933), Finnish mathematician
Lena Mellin, Swedish journalist
Ludwig August Mellin (1754–1835), Baltic German cartographer and politician
Max Mellin (1904–1977), German art director
Gustav Mellin, founder of Mellin's Food an early infant formula manufacturer
Robert Mellin (1902–1994), Russian Empire-born American composer, lyricist, and music publisher
Thomas Mellin-Olsen, Norwegian long jumper