This pilot program evaluation was undertaken to examine the effectiveness of an attachment-based, group professional-development experience, Circle of Security-Parenting, on family childcare (FCC) providers' psychological resources and self-efficacy in managing children's challenging behaviors and supporting children's socioemotional development. Licensed FCC providers with children actively in their care (n = 34) self-selected into the program, offered in English and Spanish through a regional support network for FCC providers; a comparison group of providers was recruited from the state database of licensed providers (n = 17). A significant Time x Group interaction was observed for self-efficacy in managing challenging behaviors, F(1, 46) = 30.59, p = .000, partial [eta squared] = .40, with participating providers' mean self-efficacy scores increasing, p = .000, d = .78, while comparison providers' decreased, p = .003, d = 1.40. Mean depressive symptoms decreased over time for both groups whereas job stress-related resources were stable over time in both groups. Patterns of association were found between providers' self-report of difficulties considering children's mental states and depressive symptoms, job stress resources, and self-efficacy. Limitations and implications for future research are reviewed, including the impact of conducting this work within an organized support network for FCC providers. (author abstract)