The ability to inhibit inappropriate behavior is an essential cognitive and social skill. Response inhibition of pre-potent motor responses as measured with a stop-signal or a Go/Nogo task improves throughout adolescence1,2. Performance on these tasks can be modulated by the valence of task stimuli. Inhibition of negative faces has been shown to be more difficult than that of positive faces1,3. The brain network underlying response inhibition includes the right inferior frontal gyrus (IFG), right presupplementary motor area (preSMA), and superior longitudinal fasciculus (SLF) bilaterally 4–6. The white matter underlying these regions continues to develop throughout childhood and adolescence, as indicated by in an increase in fractional anisotropy (FA), possibly reflecting ongoing myelination, and/or increase in axon diameter and density7,8. Here we used an emotional Go/Nogo task to test the hypothesis that better response inhibition (i.e. lower false alarm rate) of negative faces would be associated with higher FA in right IFG, right preSMA, and bilateral SLF in adolescents.