This paper reports the results of a two-year longitudinal study of the relationship between self-assessed intelligence (SAI) and academic performance (AP) in a sample of 184 British undergraduate students. Results showed significant correlations between SAI (both before and after taking an IQ test) and academic exam marks obtained two years later, even when IQ scores were partialled out. Several continuous assessment indicators (notably attendance, oral expression, and motivation) were also significantly correlated with SAI, even when IQ scores were controlled. A series of hierarchical regressions indicated that although exam grades were best predicted by IQ, SAI showed significant incremental validity in the prediction of AP, accounting for an additional 3% of exam, 9% of continuous assessment, and 2% of essay grades. Results are discussed with regard to current trends to integrate individual differences underlying AP. (Contains 2 tables and 1 figure.)