Urban bee ecology is an emerging field that holds promise for advancing knowledge of bee community dynamics and promoting bee conservation. Published studies of bee communities in urban and suburban habitats are fewer than those documenting bees in agricultural and wildland settings. As land lost to urbanization is predicted to increase in coming years the necessity of studying urban bee populations is growing. We reviewed 59 publications on urban bee ecology with the following goals, to assess current knowledge, to highlight areas in need of further research, and to suggest applications of study findings to bee conservation. Methodological variation between studies was discussed in the context of data interpretation. Identified trends in urban areas included the following, negative correlation between bee species richness and urban development, cavity-nesters increase in abundance in urban habitats, and floral specialists are scarce. Future directions for studying urban bee ecology include incorporation of landscape-scale assessments, conducting manipulative experiments and actively designing urban bee habitats. We include descriptions of plant and habitat management techniques derived from our research in northern and southern California urban habitats to promote development of bee-friendly habitats.