Site-level assessment questionnaires (SLAQs) were developed to assess nutrition and physical activity practices and environments in schools and other places children spend time in order to facilitate program planning and evaluation. After expert panel review for content validity, questionnaires were feasibility tested by users in six schools, three early care and education programs, and two out-of-school programs. Findings indicate that the questionnaires are feasible and useful for planning interventions. Extension programs can use SLAQs to support policy, systems, and environment change efforts that promote healthful eating and physical activity in children and to measure intervention effectiveness.