This paper presents an overview of the socio-economic situation of lesbians, gay men, bisexuals, transgender and intersex people (LGBTI), primarily in OECD countries. After investigating the size of this population, the paper zooms in on attitudes toward LGBTI, LGBTI rights and perceived discrimination among LGBTI. It goes on to discuss the empirical strategies used to identify whether LGBTI fare worse than non-LGBTI and provides a systematic review of survey-based and experimental evidence on such an “LGBTI penalty” and its causes. This exploration points to substantial hurdles for LGBTI. In particular, (i) low legal recognition of same-sex couples hampers partnership stability and children’s well-being; (ii) LGBTI are bullied at school and suffer academically; (iii) LGBTI face hiring and wage discrimination; (iv) LGBTI show higher rates of physical and mental health problems, in particular due to social rejection. The paper concludes by reviewing anti-discrimination policies and defining critical avenues for future research.