Although attentional deficits are frequently displayed by schizophrenia and spectrum patients, the precise nature of the impairment is unclear. The present study investigates attentional performance in 26 schizophrenia-spectrum outpatients and 24 healthy controls using the Attentional Network Task (ANT). We assessed the efficiency of the segregated alerting, orienting, and executive control networks by measuring how response latencies were influenced by alerting cues, spatial cues, and flanking stimuli. In overall ANOVAs we found main effects of cue condition and flanker congruency. The data also revealed a significant interaction of group and flanker type, with schizophrenia-spectrum patients taking longer on average to resolve conflict. These results suggest that compared to the healthy nonpatients, schizophrenia-spectrum patients show a deficit in their executive control network. Considered together, these findings support the notion that schizophrenia-spectrum patients have a specific attentional deficit, rather than a global one. The significance of these findings is considered from both experimental and clinical perspectives.