This report provides information on the mental health and well-being of adolescents aged 11 to 18 years old attending Luxembourg public and private schools whose teaching is based on the national curriculum in 2022. Gender differences are present across all mental health and well-being areas. In comparison to boys, girls reported lower life satisfaction and well-being, more frequent health complaints, rated their health as excellent less often, had higher prevalence of depression and anxiety symptoms, felt more often lonely and reported lower levels of self-efficacy. Other sociodemographic characteristics, such as age, family affluence, migration background, family structure and school type are included in the report. Although differences are reported, they are less marked. Furthermore, this report explores the gender gap in life satisfaction taking into account sociodemographic and psychosocial factors. The conducted analyses show that gender differences in life satisfaction are a reflection of gender differences in other psychosocial and social support factors, such as anxiety, loneliness, and family support.