Spatial thinking is a crucial aspect of geography education with which all citizens should be equipped. This study employs eye-tracking technology to research strategies (their repertoire, distribution, effectiveness, and adaptiveness) used by upper-secondary students when analyzing spatial patterns with thematic maps. The results show that students have a broad repertoire of strategies and are mostly able to adapt them to the specific task demands. Moreover, the efficiency of students' strategies gradually increases as they get familiar with the task type and the maps analyzed. Based on the findings, how to appropriately develop students' strategies in geography lessons is suggested.