It has been shown that country-level IQ and aggregated performance by school-age children on international assessment tests in math and science are by-in-large capturing analogous indicators of the cognitive human capital. We expand that analysis by comparing country-level IQ to the World Economic Forum’s Human Capital Index (HCI). This index, comprised of several dozen separate indicators, accounts for inputs and outcomes to measure human capital, across age profiles and gender. Two outcomes are of note. First, there is a positive, significant correlation between IQ and the vast majority of the component indicators in the HCI across all age cohorts. Second, because the HCI’s interpretation of educational attainment extends beyond formal education by including indicators such as on-the-job learning and other work-related skills, our finding that IQ is positively correlated with these measures suggests a deeper connection between national average IQ and the fundamental factors of what constitutes the cognitive side of human capital development.