Johan Theodorus Loevendie (born 17 September 1930 in Amsterdam) is a Dutch composer and clarinet player.
Loevendie studied composition and clarinet at the music academy (Conservatorium) of Amsterdam.
Among his many students were Svitlana Azarova, Matthias Kadar, Vanessa Lann, Peter van Onna, Robin de Raaff, Victor Varela, Sinta Wullur and Evrim Demirel.
As a performer, he participated in the ensembles Consort, Brevisand the Theo Loevendie Quintet.
It consists of a mix of western and non-western instruments: Er-hu, Viola da Gamba, Qanun, Voice, Duduk, Bass, Pan Pipes and Percussion.