This paper catalogs the provincial, municipal, and barangay-level place names—or toponyms—of the island province of Marinduque. Through close readings of primary historical sources and lexicographic texts, hypotheses on the provenance of these toponyms are forwarded. They are organized based on ten toponymic categories: physical descriptions, flora, fauna, persons, local or national events, geopolitical categories, human attributes, objects, concepts, or activities based partially on the categories in Jocano (1965), Medina (1992), Lesho and Sippola (2018), and Martynenko and Chesnokova (2019). The linguistic sources for Marinduque toponyms affirm the province’s place in the Tagalog speaking regions, but strong signals also point to contact with Bisayan and Bikol communities.