The notion of the comparison or the comparative approach to a topic is omnipresent across much of the Social Sciences, in Literary and Cultural Studies as well as in Urban Studies and related fields. Textbooks addressing the topic of comparative research as a way to link research and practice are evidence that the topic has reached the educational system as well. Still, there is no singular comprehensive theoretical or methodological approach that clearly defines the comparison. What unifies comparisons is "the aim to test, and to change, theoretical propositions" (Robinson 2015, 193). In Urban Studies, Robinson attests a track record for innovation to comparative approaches and praises the effect of comparison, which she describes as the extension of any conversation or research "beyond the single case" (2015, 194).This contribution outlines the emergence and development of comparative approaches in Urban and Metropolitan Studies from a perspective including but not limited to the Humanities. Pointing to the chances and challenges comparative approaches pose in theory and practice, it reflects on different types of comparisons and their contribution to developing and testing new ideas around interdisciplinarity and generating new forms of urban knowledge. The outlook suggests possible further developments of and challenges for working with comparisons in Urban and Metropolitan Studies.