Anxiety can be broken down into multiple facets including behavioral components, such as defensive reactivity, and cognitive components, such as distracting anxious thoughts. In a previous study, we showed that anticipation of unpredictable shocks facilitated response inhibition to infrequent no-go trials during a go/no-go task. The present study extends this work to examine the distinct contribution of defensive reactivity, measures with fear-potentiated startle, and anxious thought, assessed with thought probes, on go and no-go performance. Consistent with our prior findings, shock anticipation facilitated response inhibition (i.e., reduced errors of commission) on the no-go trials. Regression analyses showed that (a) no-go accuracy was positively associated with fear-potentiated startle and negatively associated with threat-related/task-unrelated thoughts and (b) go accuracy correlated negatively with fear-potentiated startle. Thus, while the present findings confirm the influence of anxiety on response inhibition, they also show that such influence reflects the balance between the positive effect of defensive reactivity and the negative effect of distracting anxious thoughts.