Spatial visualization is an essential prerequisite for understanding and solving many geological problems, such as interpreting the 3D structure of a complex fault system, visualizing the 3D architecture of sedimentary deposits, and visualizing the atomic structure of minerals that comprise the Earth. Undergraduate geoscience students, in both introductory and upper-level courses, bring a wide range of spatial skill levels to the classroom. Moreover, spatial thinking is multi-faceted. It is not unusual for individual students to excel at some spatial skills while struggling with others. However, spatial thinking improves with practice, and can improve more rapidly with intentional training. As a group of geoscience faculty members and cognitive psychologists, we are collaborating to apply the results of cognitive science research to the development of teaching materials to improve undergraduate geology majors' spatial thinking skills.