Attention is impaired in many neuropsychiatric disorders and by sleep disruption, leading to decreased workplace productivity and increased risk of accidents. Thus, understanding the underlying neural substrates is important for developing treatments. The basal forebrain (BF) is a brain region which degenerates in dementia and is implicated in the negative effects of sleep disruption on vigilance and cognition. Previous studies demonstrated that the BF controls cortical fast oscillations that underlie attention and revealed the important role of cholinergic neurons. However, the role of other neurochemically defined BF subtypes is unknown. Recent work has shown that one population of BF GABAergic neurons containing the calcium-binding protein parvalbumin (PV) control cortical fast oscillations and arousals from sleep but their role in awake behavior is unclear. Thus, here we test the hypothesis that BF-PV neurons modulate vigilant attention in mice. A lever release version of the rodent psychomotor vigilance test (rPVT) was used to assess vigilant attention as measured by reaction time. Brief and continuous low power optogenetic excitation of BF-PV neurons (1s,473nm@5mW) that preceded the cue light signal by 0.5s improved vigilant attention as indicated by quicker reaction times. In contrast, both sleep deprivation (8h) and optogenetic inhibition of BF-PV neurons (1s,530nm@10mW) slowed reaction times. Importantly, BF-PV excitation rescued the reaction time deficits in sleep deprived mice. These findings reveal for the first time a role for BF-PV neurons in attention.