Across the world, planning and decision-making for urban forests increasingly seeks to include diverse perspectives. Yet, research on people’s perceptions of urban forests and urban trees is fragmented. To integrate and critically analyse this body of research, we conducted a review of empirical studies about people’s perceptions of urban forests and urban trees. We analysed 178 relevant studies ... [Show full abstract] with a focus on the diversity of places, methods, people, and perception response, using text analysis algorithms in Leximancer and established epistemological and methodological content assessment frameworks. The mixed-methods-assessment-tool (MMAT) was also used to assess method quality. Findings show current literature inadequately considers diversity of places, methods, people, and perception responses. Although multiple countries are represented, studies are usually limited to a single city and address perceptions of urban trees generally or trees in parks. Convenience sampling dominates, through predetermined, survey- and intercept-based data collection techniques. Few studies have investigated the perceptions of demographically, ethnically, or culturally diverse people. Most studies focused on the positive perceptions people hold (i.e., perceptions of benefits; beliefs about the positive consequences of urban trees), rather than the diversity of perceptions that may exist. The exception is studies that focused on values, which do report more diverse perception responses. Studies often lack conceptual clarity about the specific type of perception response being investigated. Future research must consider what is being perceived, how is it being perceived, and who is perceiving it, with more clarity. There should be more emphasis on incorporating diversity in study design to better inform urban forest sustainability and resilience.