Three-dimensional thinking skills are extremely useful for geoscientists, and at the undergraduate level, these skills are often emphasized in structural geology courses. Google Earth is a powerful tool for visualizing the three-dimensional nature of data collected on the surface of Earth. The results of a 5 y pre- and posttest study of the three-dimensional visualization abilities of undergraduate students (N = 75) enrolled in a structural geology class at a small, liberal arts college are presented. The data suggest students achieved statistically significant gains in three-dimensional visualization skills over the course of the semester. Mean pretest scores for female students tended to be lower than those of male students. This gender gap, however, was no longer statistically significant in the posttest scores, with female students showing higher average gains in spatial skills compared to their male counterparts. These data show a correlation between the introduction of Google Earth map interpretation exercises, available on the Science Education Resource Center's Web site and developed by Tewksbury, and improved student visual penetrative thinking ability. Results support the hypothesis that individuals with greater contextual knowledge are able to more successfully circumvent lower three-dimensional spatial visualization ability. The exercise appears to be most effective in improving penetrative visualization ability for those students who have sufficient background knowledge. Those with less geological knowledge appear to benefit less from the Google Earth-based intervention studied here.