Accessible summary What is known on the subject A serious mental illness influences sexual life and people affected have worries about their sexual health. People living with a serious mental illness can and want to participate in interventions related to sexual health. What the paper adds to existing knowledge People who suffer a serious mental illness are interested in maintaining an active sex life. People who suffer a serious mental illness experience rejection when they open up and they lose intimate relationships or possibilities of meeting other people because of ignorance and prejudices surrounding mental health. What are the implications for practice Mental health services must respond to this need, that is including sexual needs assessment among routine standard practices or training nurses on sexual education to allow them to advise patients and their families and friends. Health systems should promote awareness programmes and reduce the stigma surrounding mental health and sexuality. Abstract Introduction Sexuality‐related nursing care is scarce and mainly focuses on biological issues. There is also a lack of knowledge about how serious mental illnesses affect sexuality. Aim To explain how people with a serious mental illness perceive and experience their sexuality. Method A meta‐synthesis was conducted to integrate qualitative studies. Four databases were used to perform the search, focused in the last ten years. Nine articles were included, and their results analysed thematically. Results Four categories were identified: "Pathologized sexuality," which explains how the disorder and treatment affect sexuality; "Not my sexuality anymore,” which describes feelings emerging from the perceived limitations and the role of self‐acceptance; “Learning to manage intimate relationships,” which explains the desire to establish intimate personal relationships and define their meaning; and "Reconstructing my sexuality," which elucidates the influence of the environment on sexuality. Discussion Sexuality is influenced by several factors, the main ones being: the clinical complications, the side effects of drug treatment, the social support, the relationship with the health sector and stigma. Implications for practice Having a serious mental illness affects sexuality and can provoke suffering and social isolation. Mental health services should address this issue and carry out community interventions to reduce stigma.