Comparison is an important geographic method and a common task in geography education. Mastering comparison is a complex competency and written comparisons are challenging tasks both for students and assessors. As yet, however, there is no set test for evaluating comparison competency nor tool for enhancing it. Moreover, little is known about university students' and prospective teachers' comparison performances and writing strategies for comparison texts. Therefore, in this study, we present an assessment tool aiming to evaluate comparison competency and assess comparison text structures. This tool can also be used as a possible scaffold to teach comparison competency. In order to evaluate the reliability and validity of the assessment tool, we tested it on a sample of 17 future geography teachers from a German university. Results showed that students possessed low levels of comparison competency, although they performed better in content-related aspects. Students utilized only a few of the available comparative text structures. Finally, results from the two parts of the assessment were positively correlated, linking comparison competency to the quality of the text structure. This shows that higher education geography programs should include content on comparison text structures when teaching comparison competency to help future teachers develop this skill.