We report two experiments exploring more in detail the bilingual advantage in conflict resolution tasks. In particular, we focus on the origin of the bilingual advantage on overall reaction times in the flanker task. Bilingual and monolingual participants were asked to perform a flanker task under different task versions. In Experiment 1, we used two low-monitoring versions where most of the trials were of just one type (either congruent or incongruent). In Experiment 2, we used two high-monitoring versions where congruent and incongruent trials were more evenly distributed. An effect of bilingualism in overall reaction times was only present in the high-monitoring condition. These results reveal that when the task at hand recruits a good deal of monitoring resources, bilinguals outperform monolinguals. This observation suggests that bilingualism may affect the monitoring processes involved in executive control.