Using a case example of one of the mental health agencies in Florida, we demonstrate the utility of concept mapping for developing a program logic model and articulating a program theory for program assessment. The results of the concept mapping procedure enabled identification of 100 program services as described in statements by staff. Moreover, results revealed four major categories of those services and the main strategies used. This information was used to develop the first three components of a logic model. Concept maps were also used to reveal underlying assumptions built into the agency's theoretical approach.