School-Wide Positive Behavioral Interventions and Supports (SWPBIS) has a large evidence base for preventing and addressing externalizing problem behavior, but there is little research examining its effects on internalizing problems, such as anxiety and depression. Given the prevalence of internalizing problems in today’s children and youth, it is worthwhile to examine the SWPBIS research base for evidence of effectiveness in preventing and treating internalizing problems. Hypothesized mechanisms by which the SWPBIS approach may support students with or at risk of internalizing problems include improving the clarity and predictability of the social environment, discouraging problem behavior that can threaten student safety, allowing instruction to take place, teaching effective responses to perceived environmental threats, and indirectly reducing internalizing problems by addressing externalizing problems. Support for internalizing challenges within a SWPBIS framework can be enhanced by adding evidence-based interventions for supporting internalizing needs within SWPBIS systems, providing professional development in identifying internalizing problems, and incorporating screening for internalizing problems into existing screening systems.