Personality is a term which for years was associated only with humans. This paper presents a review of studies and reports showing that the construct of personality can also be successfully applied to animals. The specific role of dogs in our society and the diversity observed in the exterior and interior of this species, makes it, in our opinion, a very interesting model for the study of personality. Scientists investigating personality of dogs are pursued by both theoretical and practical goals which we try to present here. We persuade that the development and dissemination of techniques for selection of animals for specific tasks and the knowledge of personality of assistance dogs seem to be very useful.