In an era marked with continuous reforms and change, school principals and teachers are called to assume more demanding roles and responsibilities. In such a context, a promising and, in some respects, unexplored way for obtaining insights into principals’ and teachers’ behaviour and motivation is by studying their efficacy beliefs. The purpose of the research in progress is to test a new model of efficacy (both self- and collective) at the school level, by exploring the relationship of the various types of efficacy of school principals and teachers in relation to the principals’ leadership behaviour. This paper reports the development of the scales that are going to be used as part of the research in progress, in order to measure self-efficacy and the collective efficacy beliefs of principals and teachers in primary schools in Cyprus.