The ability (fluid and crystallized intelligence) and nonability (personality, interests, self-concept, etc.) determinants of domain knowledge before and after an independent learning opportunity were evaluated in the context of a study of 141 adults between the ages of 18 and 69. The domain knowledge under consideration included an array of financial issues, including financial planning, retirement planning, debt management, and educational savings accounts. Crystallized intelligence was a stronger predictor than fluid intelligence of domain knowledge prior to learning, and nonability traits provided significant incremental predictive validity. After learning, fluid intelligence showed a marked increase in the prediction of domain knowledge, but the final correlation did not exceed that of crystallized intelligence. Implications for optimizing the prediction of educational success of adults are discussed.