Teachers’ enthusiasm is of considerable significance within the contemporary positive psychology as it acts as an intermediary between many other variables such as school climate and teachers’ professional attitudes. To show this role, a cluster sample of 130 female public high school teachers in Isfahan was given a set of questionnaires measuring an array of factors including attitudes and school climate. The instruments’ validity and internal consistency were confirmed. Data analyses revealed that teacher enthusiasm is only a minor mediator. However, the relation between school climate and professional attitudes was confirmed. These findings reveal that teacher enthusiasm plays a role in their professional attitudes.