HIV Pre-Exposure Prophylaxis (PrEP) is a public health strategy to reduce the probability of HIV acquisition by people at high risk of exposure. This paper addresses the perception of psychologists in the primary health care public system about the PrEP policy in the state of Mato Grosso, Brazil. Through semi-structured interviews, we sought to understand the therapeutic itinerary in the unit where it takes, as well as the opinions and involvement of the psychologists in the implementation of PrEP. There is a lack of definition regarding the attributions and scope of action of the psychologist in relation to PrEP in health units. In some, reception is mandatory in the first service, in others only if there is a request from the user. The interviews revealed that there are distrust and prejudice in relation to the policy and users' social behaviour, as well as the recognition of the lack of training and dissemination as the primary motivations for the low adherence. Psychologists proved to be important professionals in implementing PrEP. Notwithstanding, more dialogue is needed with management at the local and state level so that doubts, beliefs, and social representations are discussed and do not compromise the effectiveness of the policy.