The transfer and adoption of the school-wide positive behavior support (SWPBS) framework in different contexts worldwide is receiving increased interest. Identified challenges in implementing relevant systems and practices with fidelity at local schools can lead to adaptations improving the contextual fit of SWPBS, which eventually contributes to enhanced outcomes. The present study documents a 2-year systematic implementation of SWPBS in 31 elementary schools in Cyprus. Cultural and situational barriers were identified using a mixed-methods design. Data were obtained from three fidelity assessments across time, through which we examined the schools' efforts to integrate SWPBS elements into their setting. School size and location were also used to predict implementation fidelity. External coaches' experiences working with schools for 2 years were summarized to provide insight into the main impediments to effective implementation. Recommendations for forthcoming applications of SWPBS in contexts with similar characteristics are drawn.