It has been proposed that dispositional optimism is positively associated with treatment program engagement. However, conflicting evidence exists regarding this relationship. We examined whether the importance of a treatment goal moderates this association. In Study 1 (N = 95), individuals high in optimism were more interested in attending a nutrition education program when the importance of nutrition was first highlighted. In Study 2 (N = 91), participants were given the opportunity to attend psychotherapy to address an academic problem. Dispositional optimism was associated with greater treatment attendance when participants rated their problems as high, relative to low, in importance. It is concluded that the personality variable of dispositional optimism does relate to interest and attendance in treatment, however, treatment goal importance moderates these relationships. It is recommended that practitioners and researchers take an interactionist approach when assessing the role of personality and situational factors in treatment program interest and attendance.