<p>Despite growing research on the use of evidence-based practices (EBPs) in schools, many fail to be implemented with fidelity and sustained over time. Implementation science offers a framework to address this gap through examining contextual variables that impact school-based implementation. In practice, there are different determinants of implementation; facilitators promote implementation, and barriers inhibit implementation. Educators encounter numerous implementation barriers that can hinder treatment fidelity, but little is known about broad contextual variables in schools. This survey study analyzed responses from 298 in-service teachers to explore perceived implementation barriers and facilitators, organized into inner and outer context variables. Inner context variables included Resources, Training, Support, and Implementer Characteristics, while outer context variables included School, Family, District, and Community influences. Teachers indicated how often the implementation variable were present in their setting; overall responses were summarized as barriers or facilitators. Results indicated that teachers mainly identified lack of resources and insufficient training as inner context barriers. However, school leadership, district alignment, and parent investment were viewed as implementation facilitators. Community-level support, implementation support, and implementer motivation and self-efficacy were more mixed, with some items representing a barrier and others a facilitator. Implications for practice and future research directions are discussed.</p>