Physical activity patterns within the U.S. vary greatly across ethnicity, with data generally indicating lower rates among Hispanic/Latino adults. At the same time, Hispanic/Latino pedestrians face higher rates of injury and fatalities. Despite the importance of supportive physical activity environments on both health and safety outcomes, limited attention has been paid to ethnic or cultural differences in perceptions of supportive environments for walking. To fill this gap, we explore differences in physical and social environment contributors to perceived walkability between pedestrians in predominantly (> 70%) Mexican American and predominantly non-Hispanic white areas in Tucson, Arizona.In early 2017 the research team conducted brief on-street intercept interviews with pedestrians (N = 190) to learn about the environmental attributes associated with pedestrian perceptions of walkability. Study locations were matched for similar physical walkability metrics, income, and poverty rates. Consensus-based thematic coding identified 14 attributes of the built and social environment that contributed, positively and negatively, to perceptions of walkability.Attributes of the social environment, both positive (i.e., social interaction, social cohesion, and community identity) and negative (i.e., crime/security), were more frequently expressed as components of walkability in Mexican American study areas while physical environment attributes (i.e., infrastructure, street crossings, and aesthetics) were more frequently mentioned in non-Hispanic white areas.Contributors to perceived walkability in non-Hispanic white study areas were largely consistent with existing built environment-focused walkability metrics. Differences seen in Mexican American areas suggest a need to better understand differences across populations, expand the construct of walkability to consider social environment attributes, and account for interactions between social and physical environments. Results highlight the need for collaboration between public health and planning professionals, to evaluate walkability using culturally relevant measures that account for the social environment, particularly in Mexican American and other communities of color.