Investigated the relation among response inhibition, hyperactivity, and conduct problems in a nonclinical sample of 115 preschool children, using 2 different types of go/no-go tasks well as a Stroop-like task. In line with the assumption that hyperactivity is related to disinhibition, the results showed that it was the measures of response inhibition, and not other performance measures, that were related to teacher ratings of hyperactivity. There was also a significant relation between response inhibition and conduct problems. Interestingly, the correlation between response inhibition and conduct problems was not significant when partialling out the effect of hyperactivity, whereas the correlation between inhibition and hyperactivity did remain significant when controlling for conduct problems. Although the association between inhibition, hyperactivity, and conduct problems appeared to be partly different for boys and girls, these differences were not statistically significant.