This paper explores the toponymy of Trilj, a subject that has not been previously studied. The primary source of data comes from the latest cadastral survey, supplemented and compared with findings from field research. Before the analysis of toponyms, the paper presents a concise overview of the Trilj dialect at all linguistic levels, along with a brief historical overview of the region. The main part of the study is a chapter that catalogues and examines the toponyms of Trilj. Each toponym is analyzed in terms of its etymological origin, the specific location it designates, and the connection between linguistic expression and extralinguistic reality. Etymological analysis reveals that the majority of toponyms are of Slavic origin (Okolište, Steljak). Several toponyms of Romance origin have also been recorded, which can be cathegorized into older toponyms originating from Latin (Lastva) and more recent ones from Italian (Bušak). Furthermore, the study identifies toponyms of Oriental (Biserka, Općaluk), Greek (Livada, Žal), and French (Piket) origin. Most of the toponyms reflect human activity, particularly agriculture, as well as geographic features.