The purpose of this study was to develop the Scale for Program Facilitators (SPF) to assess the effectiveness of after school achievement programs through four steps: (a) identification of a theoretical framework, (b) formulation of the initial scale, (c) test of content validity, and (d) conducting confirmatory factor analyses (CFA). A comprehensive review of literature revealed that after school programs commonly have four key objectives: (a) Scholastic Development, (b) Social Behavior, (c) Caring Environment, and (d) Personal Inspiration. The preliminary scale with 18 items was formulated by following these objectives as the theoretical framework, along with conducting a review of literature, on-site observations, interviews with program facilitators, and conducting a test of content validity by a panel of experts. Research participants (N = 2,995) were program facilitators, who were asked to use the preliminary SPF scale to evaluate the program attendees under their direct supervision. Adopting the Maximum Likelihood and the Weighted Least Squares estimation methods in the CFA, the four-factor model was confirmed providing good fit to the data. Discussions were made in the context of the scale development and its potential application in evaluating after school programs.