Pierre Ancelin (October 25, 1934 – December 19, 2001) was a French composer.Born in Cannes, Ancelin studied pedagogy and music history at the conservatories of Aix-en-Provence and Marseille, then followed the course of aesthetics of Olivier Messiaen in Paris.He was mostly self-taught in composition and orchestration, although he followed the advice of Ernest Ansermet and Frank Martin. From 1963, he worked regularly in French literature and various music magazines abroad.
In 1975, he founded the UNCM (National Union of Composers of Music) with Andre Jolivet, Daniel Lesur and Henri Sauguet. He presided over the union until 2000.