Early child care and education providers provide instruction to diverse learners, including children with developmental delays but often lack training in use of evidence-based instructional strategies to support children's meaningful learning engagement. This preliminary study examined effects of the Early Achievements for Child Care Providers professional development program with and without generalization training on center-based child care providers. Outcomes assessed included providers' (N = 12) implementation fidelity, knowledge, and self-efficacy as well as children's (N = 43) social-communication skills and engagement in shared book reading. Results demonstrated that providers trained in a generalization context made larger gains in implementation fidelity in a generalization context; no other significant between-group differences were found for providers. Children in both groups made comparable, significant gains. Findings suggest that explicit generalization training is needed for providers to achieve fidelity when transferring newly learned evidence-based practices to additional classroom instructional contexts, but a brief interval of implementation likely is insufficient to affect child outcomes. Researchers should elicit providers' perceptions when designing professional development programs to maximize feasibility of investing additional time and resources for generalization training. [This paper was published in "Early Childhood Education Journal."]