This research investigated whether completing an introductory GIS course affects college students' spatial literacy as defined by spatial habits of mind, spatial concepts and thinking skills, and critical spatial thinking. This study employed three tests (spatial habits of mind inventory, spatial concepts and skills test, critical spatial thinking oral test) to measure students' performance on these three elements. Furthermore, this research investigated the relationship among the components. Pre- and post-tests were conducted at the beginning and the end of the 2010 fall semester, and Texas A&M undergraduate students participated in the research. The following four research questions were examined. The first research question investigated whether GIS learning improves spatial habits of mind (n = 168). Five sub-dimensions of spatial habits of mind (pattern recognition, spatial description, visualization, spatial concept use, and spatial tool use) were identified. Overall, GIS students' spatial habits of mind were enhanced. However, variations existed when considering students' performance by dimension. The second research question explored whether GIS learning affects students' understanding and use of spatial concepts and thinking skills (n = 171). This research found that the GIS course was beneficial in improving students' spatial cognition. Students increased their understanding of key spatial concepts and applied conceptual understanding into wider contexts with advanced spatial thinking skills. The third research question examined the effects of a GIS course through interviews on the three sub-dimensions of critical spatial thinking: data reliability, spatial reasoning, and problem-solving validity (n = 32). The quantitative analyses indicated that participants developed their ability regarding these three sub-dimensions of critical spatial thinking. In particular, their ability to assess data reliability and problem-solving validity improved, an effect not likely to be enhanced by other coursework. Findings from qualitative thematic analysis confirmed these quantitative outcomes. The final research question probed the relationships among the three components of spatial literacy. Pearson?s correlation coefficient, a 3D space (termed "score space" in this study), a test for independence, and an exploratory factor analysis suggested that the three components are positively correlated. However, more research is necessary to confirm the results reported in this study.