To compare physician assistant (PA) students' attitudes regarding interprofessional education by students' seniority, gender, age, and previous experience with interprofessional education. The validated 19-item Readiness for Interprofessional Learning Scale and the 12-item Interdisciplinary Education Perception Scale were administered to matriculating and graduating PA students from 2 US institutions (N = 186). Primary outcomes were score differences by subgroup and institution using independent sample t-tests. We also examined scale validity measured by Cronbach's alpha (internal consistency) and Pearson correlation coefficients (concurrent validity). Student demographics at both institutions were similar. Initial comparisons did not demonstrate significant institutional differences. Consequently, data were combined for subsequent analyses. Matriculating students had significantly higher mean Readiness for Interprofessional Learning Scale scores than did graduating students. No significant differences were found by gender, age, or previous interprofessional education exposure for either scale. Both scales demonstrated high internal consistency (Readiness for Interprofessional Learning Scale α = 0.93; Interdisciplinary Education Perception Scale α = 0.84). Physician assistant student attitudes regarding interprofessional education are very positive at matriculation and are less positive at graduation. Physician assistant student attitudes do not vary by gender, age, or previous interprofessional education exposure. Physician assistant educators should ensure that students' interprofessional education exposure makes full use of the students' initial positive attitudes and focuses on skill development for interprofessional education competencies.