ABSTRACT: Community based environmental groups have become an integral component of urban environmental stewardship initiatives in Perth metropolitan area. While the utility of Urban Environmental Groups (UEGs) has been recognized by several environmental policies and programs, the challenges of sustaining UEGs remain under-explored, especially, in Western Australia. This paper responds to this gap and explores the prospect of UEGs’ sustainability through the lens of social capital. The findings of a quantitative survey of 81 groups as well as qualitative observations suggest UEGs that are better at building and maintaining social capital are more likely to overcome resource-scarcities and sustain over time. Based on the findings, the paper views social capital as a necessary ingredient of sustainable community groups and discusses the strategic needs to support UEGs.