We present psychometric evidence for the BFAS-40, an abbreviated measure of the Big Five Aspects Scale (DeYoung et al., 2007). In Study 1, we developed the BFAS-40 using metaheuristic algorithms and cross-validated the factor structure of the shortened measure. In Study 2, we demonstrated that the BFAS and BFAS-40 correlate with external criteria in similar ways. In Studies 3 and 4, we provide convergent validity evidence by examining correlations between the BFAS-40 and other measures of typical and clinically relevant personality. Finally, in Study 5, we provide evidence of test-retest reliability as well as additional construct validity evidence. Across these five studies, we demonstrate that the BFAS-40 is a short, reliable, and valid measure of the Big Five Aspects.