Paraprofessionals are critical school staff often responsible for students with or at risk for academic, behavioral, and social impairments. However, research on paraprofessional roles, professional development, and training needs is very limited. The present mixed-method study seeks to fill this gap by examining the student populations served, paraprofessionals' reported work setting, available professional development, and training needs. In a sample of 215 paraprofessionals from 62 schools, results indicated that paraprofessionals deliver interventions and supports to individual and small groups of students, often serve students who exhibit disruptive classroom behavior, and students who are eligible for special education services. Work setting consists primarily of a single classroom (general or special education) with multiple students. Paraprofessionals reported receiving 1-2 h of workshop-based professional development per year which is not job-embedded in the classroom settings. Nearly all participants reported the need for additional training in one or more topic areas with behavior management strategies, the most frequently identified are of training need. Implications for practice are discussed. [For the corresponding grantee submission, see ED614480.]