Parental beliefs are recognised by psychologists as an important causal influence on child development. A two-period model of human capital accumulation in the framework of Becker and Tomes (1986) is presented. In the first period parents transfer their beliefs, distinct from genes, to children by signalling their ‘belief in a just world’ or their perceived return to effort. Children respond by choosing effort, irrespective of the real world returns, which combines with their genes to create early ability. This determines the rate of return to second-period investment and final attainment. If parents are credit constrained, both beliefs and income determine attainment. Empirical analysis using the second generation of the NCDS shows that beliefs are a strong predictor of early attainment and significantly reduce the importance of parental income. The identifying assumption is that parent beliefs are slow-moving and not conditioned on the child.