The crux of this paper lies in exploring geographic information system (GIS) adoption and diffusion among high school geography teachers in Taiwan. Because the integration of GIS in the high school curriculum is relatively new, we assume that high school geography teachers require resources, training, and assistance in learning GIS and in developing modules that can be incorporated into their teaching. A number of in-service training programs have been created to this end. We aim to study what motivates geography teachers to learn GIS during in-service training. The adoption of GIS has been studied in countries such as the U.S. and Singapore; however, as there is presently no literature on Taiwan's experience, we intend to fill this gap. This is achieved through statistical analysis of primary data gleaned from a census of Taiwan's high school geography teachers. The design of the questionnaire is largely inspired by an existing measurement of two commonly cited theoretical models. The technology acceptance model (TAM) and its various modifications focus on teachers' perceived usefulness (PU) and perceived ease of use (PEOU). The social influence model (SIM), differently, postulates that teachers' usage of GIS is affected by peers and their schools. Using the census data, we provide a preliminary analysis of these two models in this paper.