Barkley's hybrid model of executive functions (EFs) predicts that individuals with deficient inhibitory control should show impairment of EFs. Thirty-eight nonreferred young adults were administered tests of EFs and four laboratory measures of inhibitory control: Stop Signal (SS), Go No-Go, Competing Motor Program (CMP), and Stroop Color-Word tests. Behavioral ratings of impulsivity were collected using the Barratt Impulsivity Scale-11 (BIS-11). CMP and SS accounted for a significant proportion of variance in measures of EFs beyond that accounted for by IQ. Additionally, increased impulsivity, as measured by the BIS-11, was associated with poorer performance on some tests of EFs. These findings provide partial support for Barkley's theory in that effective executive functioning is associated with sufficient inhibitory control.