Geoff, the geospatial form and function vocabulary, is a comprehensive RDF-based spatial object classification scheme based on a separation of the concepts of form and function. Geoff is based on our analysis of the extensive (over 50 million spatial object instances) Digital Landscape Model (DLM) Core model maintained by Ordnance Survey Ireland (OSi). We propose Geoff as there are currently no open geospatial form and function classification systems that cover the full range of geospatial objects (from buildings and roads to lakes and other natural features) modelled as Linked Data or in any other formalism. Geoff is a generalization of the DLM Core schema and adopts the GeoSPARQL ontology. Geoff was initially developed to make these classifications available for OSi’s geospatial Linked Data as they facilitate the publications of more expressive models of spatial features. For example, to state that a church building (form) is now used as apartments (function). Geoff is now presented to the wider community for reuse and extension to meet their own needs. Geoff supports geospatial queries based on form and function and interlinking of geo-information datasets using different form and function code lists. The Geoff ontology follows Linked Data publishing best practice in terms of available metadata, documentation, and quality assurance.