Close, S., Fisher, D., Yagatichb, W., Gallib, A. 2016. Evaluating the environmental effectiveness of grassroots environmental stewardship organizations in Maryland, USA. Watershed Science Bulletin May 2016. Center for Watershed Protection, Ellicott City, MD. Small organizations that conduct environmental stewardship projects often lack access to the research capacity, funding, or tools needed to evaluate scientifically the environmental effectiveness of the measures they undertake. Still, evaluation of environmental effectiveness, defined here as the implementation of specific local goals, is prudent where projects are carried out with environmental stewardship goals in mind. We propose and test a process for evaluating environmental effectiveness of stewardship programs in a rigorous, yet feasible, approach through analysis of archived documents, program materials, and project inventories, as well as a survey of program participants. Using three franchises of the Watershed Stewards Academy in Maryland as a case study, the authors evaluate the environmental effectiveness of the stewardship work conducted by these organizations.