Although critiqued for circular reasoning and lack of definitional and analytic clarity, social capital has garnered widespread interest in two areas relevant to environmental education (EE): the impact of family and community-level social capital on positive youth development and of community-level social capital in fostering collective action to manage natural resources. Although EE is normally considered for its value relative to environmental outcomes or natural capital, intergenerational, community, and other approaches to EE may also foster social capital. Drawing on Putnam's definition of social capital, which emphasizes civic engagement, we developed and tested for reliability a survey to measure cognitive and structural attributes of social capital among youth. We conclude that although several attributes of our instrument are useful for use with youth aged 10-18 years in EE contexts, much more work needs to be done on conceptualizing and developing measures of social capital that are relevant to EE. Further, we suggest that social capital presents a framework for how EE programs can bring youth and adults together to create the conditions that enable collective action, as a complement to ongoing work in EE focusing on individual behaviors.