Student positions on the relationship between biological evolution and divine creation have been examined in a range of contexts, and although there is evidence that students can change their position on the relationship over a period of study, these changes have not been well characterized or fully quantified. To investigate student changes in position on the relationship between evolution and creation, we synthesized existing literature to develop a new research tool covering eight positions and including a question probing reasons for changes in position. Buddhist and Christian high school students undertaking a course on evolution at a Christian school in Thailand (N?=?125, mean age 17.6) responded to a survey to elicit their positions before and after a course and reasons for any changes. Analysis revealed that a high proportion of students underwent a change in position, primarily towards increasing acceptance of evolution, a trend that was clearest among Christian students. Participants reported that these changes were influenced by changes in their understanding of the evidence for evolution and of ways of relating evolution and their religious beliefs, but not by changes in their religious beliefs. The study shows that the tool is effective for detecting changes in position and eliciting key reasons for these changes. Moreover, it points to the importance during evolution education of focusing on the evidence for evolution and the relationship between science and religion.