As parental competencies are of importance for the development of children, these competencies are often fostered in parent training programs. Research suggests that a lack of fit between training contents and parental perceptions and expectations might result in a lower effectiveness of a parent training. Consequently, parents’ subjective perceptions of trainings should be in the focus of research on the effects of parent trainings. The present study evaluated the effectiveness of a parent training (MonteBaRo-Training) and analyzed pre-post-test changes. Parents who participated in the program (N = 117) and a waiting list control group (N = 88) were surveyed about children’s behavior problems, parenting sense of competence and dysfunctional parenting at two measurement occasions. Results indicated that the training was effective in improving parenting sense of competence, the perceptions of child problem behavior and dysfunctional parenting. Subjectively perceived usefulness of the training was associated with a change in children’s behavior problems and the parenting sense of competence after the completion of the course.