Background: The field of postgraduate medical education (PGME) is continuously evolving as a result of social demands and advancing educational insights. Change experts contend that organizational readiness for change (ORC) is a critical precursor for successful implementation of change initiatives. However, in PGME, assessing change readiness is rarely considered while it could be of great value for managing educational change such as curriculum change. Therefore, in a previous Delphi study the authors developed an instrument for assessing ORC in PGME: Specialty Training’s Organizational Readiness for curriculum Change (STORC). In this study, the psychometric properties of this questionnaire were further explored. Methods: In 2015, STORC was distributed among clinical teaching teams in the Netherlands. The authors conducted a confirmatory factor analysis on the internal factor structure of STORC. The reliability of the measurements was estimated by calculating Cronbach’s alpha for all sub-scales. Additionally, a behavioral support-for-change measure was distributed as well to assess correlations with change-related behavior. Results: In total, the STORC questionnaire was completed by 856 clinical teaching team mem-bers from 39 specialties. Factor analysis led to the removal of 1 item but supported the expected factor structure with very good fit for the other 43 items. Supportive behavior was positively correlated to a higher level of ORC. Discussion: In this study, additional steps to collect validity evidence for the STORC questionnaire were taken successfully. The final subscales of STORC represent the core components of ORC in the literature. By breaking down this concept into multiple measurable aspects, STORC could help to enable educational leaders to diagnose possible hurdles in implementation processes and to perform specifically targeted interventions when needed.