Ruben Radica (born 19 May 1931) is a Croatian composer. He was born in Split, and acquired a music grounding from his grandfather, the composer Josip Hatze. At the Zagreb Academy he graduated from the conducting class of Slavko Zlatić (1957) and from the composition class of Milko Kelemen (1958). In addition he attended classes in Siena, Paris and Darmstadt, given by Vito Frazzi, René Leibowitz, Olivier Messiaen, György Ligeti, Pierre Boulez and Henri Pousseur. Radica taught at the Sarajevo Music Academy from 1959 to 1963, and then joined the faculty of the Zagreb Academy, lecturing in musical theory.