The amount of family financial resources available in early life influences child health and development. Using data from the 2000 and 2007 waves of the Indonesian Family Life Survey, we estimated the associations of earlylife poverty (at age <7 years) and poverty in later childhood (at age 7-14 years) with cognitive function at age 7-14 years. Our analysis provided little support for the idea that an early intervention to support household income has a larger effect than intervention later in childhood; both seemed equally important. We also decomposed the effect of poverty at age <7 years into direct and indirect effects mediated through poverty and schooling/home environment at age 7-14 years. For decomposing the effects, we used 3 approaches: 1) joint mediators, 2) path-specific, and 3) intervention analog. Being exposed to poverty before age 7 years had a larger direct effect (difference in cognitive function z score) on child cognitive function at age 7-14 years (i.e., joint mediators β = -0.07, 95% confidence interval: -0.12, -0.02) than the indirect effects mediated through later poverty at age 7-14 years (β = -0.01, 95% confidence interval: -0.04, 0.01) and school attendance/home environment at age 7-14 years. The effect of poverty on cognitive function was small; nevertheless, financial interventionmay still benefit children's cognitive function.