Conditions referred to as ‘male sexual dysfunctions’ usually include erectile dysfunction, ejaculatory disorders and male hypogonadism. However, some less common male sexual disorders exist, which are under-recognized and under-treated, leading to considerable morbidity, with adverse effects on individuals’ sexual health and relationships. Such conditions include post-finasteride syndrome, restless genital syndrome, post-orgasmic illness syndrome, post-selective serotonin reuptake inhibitor (SSRI) sexual dysfunction, hard–flaccid syndrome, sleep-related painful erections and post-retinoid sexual dysfunction. Information about these disorders usually originates from case–control trials or small case series; thus, the published literature is scarce. As the aetiology of these diseases has not been fully elucidated, the optimal investigational work-up and therapy are not well defined, and the available options cannot, therefore, adequately address patients’ sexual problems and implement appropriate treatment. Thus, larger-scale studies — including prospective trials and comprehensive case registries — are crucial to better understand the aetiology, prevalence and clinical characteristics of these conditions. Furthermore, collaborative efforts among researchers, health-care professionals and patient advocacy groups will be essential in order to develop evidence-based guidelines and novel therapeutic approaches that can effectively address these disorders. By advancing our understanding and refining treatment strategies, we can strive towards improving the quality of life and fostering healthier sexual relationships for individuals suffering from these rare sexual disorders.