The health and safety of LGBTQI+ migrants or migrants who are of diverse sexual orientation, gender identity or expression (SOGIE) remains an under-studied area, particularly for the period during transit from their place of origin to destination. This systematic review aims to describe the literature on the health risks and consequences among SOGIE migrants during transit and examine their access and use of services. Six peer-reviewed databases and websites of nine large migration organisations were searched to identify the literature on forced migrants and sexual and gender minorities. Twenty English-language studies from 2000-2021 were included and analysed drawing on a conceptual framework. Studies emerged from six regions and the majority of research participants identified as gay men. In general, quality appraisal demonstrated studies as either medium or high quality. Findings suggested five common themes associated with SOGIE health and well-being, including: daily exposure to discrimination, harassment and violence; coping, social support and resilience; access to services; mental health; and physical and sexual health. Depression, anxiety and post-traumatic stress disorder (PTSD) were prevalent amongst SOGIE migrants, particularly when associated with detention or camp environments, and were exacerbated by social isolation. Barriers to accessing healthcare were identified and specific sexual health services were often found lacking, especially for trans persons. Unsurprisingly, during transit, SOGIE migrants are very likely to experience the double marginalisation of their migrant or minority status and their gender identity. Results indicate that services for SOGIE migrants need to tailor service access and support approaches to respond to the particular health and protection needs of SOGIE individuals in each setting.