Objectives: The success of a Dutch program to disseminate quality improvement projects depends on the participation of physicians working in program hospitals. The leadership of hospital executives (CEOs) is considered an important explanation. This study aims to determine whether the relation, between the extent to which physicians notice their CEOs stimulate improvement initiatives and the number of projects joined by physicians, is moderated by the consensus among physicians working in the same hospital. Methods: Multilevel analyses are applied on data of 286 physicians from eight hospitals to: (1) estimate whether participation depends on noticing if CEOs stimulate improvement, (2) test if an individual’s participation differs when more colleagues have the same opinion (effect modification). Results: Significant moderator effects are found. The participation of physicians, noticing that CEOs stimulate improvement is higher when more colleagues share this opinion. For physicians not knowing whether improvement is encouraged, higher consensus coincides with lower participation. Conclusion: Project involvement of physicians depends on their consensus about encouragement by CEOs. This confirms the importance of strategic leaders in dissemination programs. Further research is recommended into causes of CEO leadership visibility and methods to strengthen leadership climate.