Informal institutions are defined as socially shared rules that guide individuals' behaviors outside of officially sanctioned channels. This paper investigates the link between individual educational attainment and education-related informal institutions by examining second-generation immigrants in the USA. I measure the education-related informal institutions by average educational attainment among the adult population conditional on per capita GDP in the second generation's country of ancestry. Empirical analysis shows that given similar family background, market, and institutions, higher average educational attainment in the origin country predicts more years of individual schooling; this relationship is stronger among those with less educated parents. These findings are robust to various methods of controlling for unobserved human capital, alternative sample criteria, and alternative measures of informal institutions (JEL I20, J15, Z10).