Chronic pediatric illnesses are common and they are often educationally consequential. Many chronically ill children experience severe educational impairments. Empirical research on the pediatric illness–schooling interface notwithstanding, theoretical endeavors on the topic are largely missing. This chapter presents a theoretical model comprising four interrelated dimensions. These are the nature and severity of the pediatric illness itself (e.g., asthma, epilepsy), educational challenges common to each illness (e.g., direct neurocognitive effects, uninformed teachers), students’ personal strengths (e.g., emotional resilience), and environmental supports (e.g., social supports at school). These three dimensions are hypothesized to mutually determine the nature and severity of any adverse educational impacts (e.g., academic or attendance problems). The model is abbreviated as P-CSI, to denote Pediatric, Challenges, Strengths/Supports, and Impacts. It is argued that the P-CSI model helps contextualize existing information on prevention and intervention. It may also reveal gaps to be addressed by future research concerning pediatric illnesses at school.