Purpose: This study aimed to evaluate the impact of four cross-institutional teaching enhancement projects (TEPs), a relatively new form of professional collaboration. The focus is on the impact at departmental, institutional and cross-institutional levels because such impact is the main reason for establishing cross-institutional TEPs. Design/methodology/approach: A professional capital framework guided the examination of decisional and social capitals at departmental, institutional and cross-institutional levels. A theory-of-change method was adopted to collect data from 35 sets of documents, 22 project members and 65 stakeholders. Findings: The authors found five forms of impact, showing the development of decisional and social capitals mostly at institutional and cross-institutional levels, whilst signaling the relatively weak impact at departmental levels. Therefore, the values of cross-institutional TEPs have not been fully realized and future endeavors need to better utilize the capitals in programs. Originality/value: Few studies evaluated the impact of large-scale, cross-institutional TEPs. The authors offered new contributions by gauging the impact of these under-explored forms of complex professional collaborations.