The purpose of our article is to research the functions of inner dialogue while driving a car. We assumed the following: (1) driver is aware of the inner dialogue; (2) inner dialogue affects driving style; and (3) negative inner dialogue increases aggressive driving of car drivers. To answer those questions, we describe various theories of inner dialogue and (aggressive) driving. Further, we connect and present inner dialogue and aggressive driving within the theoretical model of impact of inner dialogue on aggressive driving. Connectedness of inner dialogue and aggressive driving is also checked using qualitative research with a population sample of 29 Slovenian drivers. The results of the research show that drivers are aware of inner dialogue while driving, evaluative, self-directing and self-encouraging functions of inner dialogue are present while driving a car, that inner dialogue co-influences the emergence of aggressive driving, and inner dialogue of aggressive drivers is negative.