Fear of thinking is a common symptom in adolescence. This paper looks at this fear through the lens of masochism. The author focuses her interest on three types of masochism - erogenous, feminine and moral - which make it possible to elucidate different functions of this “avoidance of thought in thinking”: protection against excess psychic excitation (erogenous masochism); management of the fear of dispossession or penetration of one's thoughts (feminine masochism); the result of a prohibition to think due to an unconscious feeling of guilt (moral masochism). The author advances the hypothesis that fear of thinking does not originate solely in the phantasized power attributed to identificatory objects (primary and Oedipal), but also concerns the thinking process itself, given its capacity to link and associate representations. The theoretical discussion is supported by the presentation of the clinical case of a hospitalized adolescent girl, seen from the perspective of the transferential dynamics in the meetings with the Department psychologist.