Education and mental health shape individuals’ wellbeing and their opportunities in life. Understanding the relationship between these two domains and their intergenerational transmission is valuable for researchers, policy makers, and society as a whole. With this doctoral dissertation, I tried to further our understanding of the causes of individual differences in educational outcomes, their relationship with mental health, and their co-intergenerational transmission. In my research I worked with observational data in large samples, triangulating across several genetically-informed designs to study genetic and environmental transmissions.