Common practice has proven that software implementations of environmental models are seldom reused by broader communities or in different modelling frameworks. One of the reasons for this situation is the poor semantics of model interfaces. Model interfaces describe a critical amount of the modellers’ knowledge, but their software implementations fail to represent the complexity of model assumptions in software terms. In this paper, we present an ontology-driven approach that aims to enrich software model interfaces with advanced semantics. A generic ontology for defining environmental model variables has been developed along with two families of tools for supporting the modellers’ community to share their knowledge and software codes in an easy, efficient and sound way. The first family of tools consists of a web-based ontology editor for sharing knowledge related to environmental model components and their interface variables. The second set of tools exploits the knowledge stored in the ontology by generating source code in an automated fashion. Thus, it is shown how ontologies, accompanied by a set of supporting tools, can be used for promoting the reuse of environmental models.