Gaze-based interactions (GBIs) allow hands-free control and richer user experiences across domains. Yet, despite eye-tracking's diagnostic use in geospatial visualisations, its potential for interactive spatial data exploration is underexplored. By providing a scoping review of the integration of GBIs into geospatial visualisations, we aim to lay the foundation for further research, as no comprehensive review has yet been carried out.Using the PRISMA-ScR framework, we assessed 26 studies employing 54 GBIs. We developed an open-source web dashboard to simplify the interpretation of multiple data items across GBIs. Most GBIs (74.1%) relied solely on gaze, with 68.5% using remote eye-trackers. Active interactions dominated (64.2%), primarily for discrete commands concerning zooming, panning, or selecting map elements. Meanwhile, passive interactions focused on gaze-informed adaptations, such as automatically updating legend content based on in-map attention. Although there were accuracy and unintended activation issues, GBIs often improved the hedonic and pragmatic quality of geovisualisations.Studies would benefit from robust user evaluations that use standardised questionnaires. Broader GBI research solutions, such as combining gaze with other modalities in extended reality, could transform how we interact with geospatial data.