INTRODUCTION: Transgender people face against significant barriers in accessing mental health services due to, among other reasons, discrimination and a lack of expertise among professionals. To explore the beliefs and attitudes of professionals in the mental health network of the region of Murcia towards transgender people, focusing on aspects such as knowledge, perceptions, and prejudices about gender identity. We carried out a qualitative study involving 14 participants, conducting semi-structured interviews based on prior knowledge of the topic. We asked the professionals about their experiences and challenges in their clinical interaction with transgender users and followed an inductive-deductive process to analyse the data. Two main themes were identified from the interviews, which were sub-categorised into different sub-themes: (a) beliefs about transgender people: underlying factors and origins of gender diversity, health needs, and stereotypes about the demand for health care; (b) attitudes and behaviours of professionals towards transgender people: pathologization and attitudes towards decision-making. Our findings suggest that mental health professionals tend to oversimplify the factors underlying gender diversity and hold certain stereotypical beliefs about these users that oversimplify the complexity of their experiences.