The purpose of this article is to provide an overview of priorities for evaluation capacity building in the voluntary/nonprofit sector and to raise awareness among evaluation professionals of the key issues for nonprofits that may have an effect on evaluations. There are various challenges for nonprofit organizations in the evaluation of their programs, projects and activities that include the availability of resources, evaluation skill levels, the design of evaluations and the nature of nonprofit work. Among the priorities for evaluation capacity building in the nonprofit sector that emerge from these challenges are: fostering collaboration; addressing resource and skill needs; exploring methodological challenges; and building a feedback loop into evaluation. There is presently a large opportunity to open the dialogue process in evaluation, for nonprofits to work together and for nonprofits to work with funders and evaluators to address evaluation challenges. Evaluators have a role to play in meeting evaluation challenges in nonprofit organizations by helping to find strategies for affecting change, exchanging information with the nonprofit sector community on advances being made in this area and ensuring that efforts are sustainable.