Catholicon may refer to:
- Catholicon, the conventual church at the centre of an abbey
- Katholikon, the primary church in an Orthodox or Eastern Catholic monastery
- Catholicon (Mor Yakub), part of the Holy Liturgy of Mor Yakub of the Syriac Orthodox Church
- Catholicon (book), written in 1286 by Johannes de Balbis of Genoa (Summa grammaticalis quae vocatur Catholicon)
- Catholicon (Lagadeuc), Breton–Latin–French dictionary written in 1464 by Jehan Lagadeuc and printed in 1499
- Catholicon (electuary), an alleged all-purpose cure (panacea) used in pre-modern medicine