This article analyses the influences of psychology on social work. An examination of classical approaches reveals that some have a more significant influence than others: a) evolutionary psychology has a highly negative effect on fairness among persons; b) psychoanalysis impacts on the family as a social entity, c) behaviourism designs models for changing social behaviour; and d) humanism, existentialism and Gestalt psychology use empathy as a means to improve communication. These theoretical models and psychological methods are socially efficient in influencing the professional tasks and practices of social workers in various fields.