Purpose Individuals in the acute and chronic stages of stroke recovery often report more daytime sleepiness (Sterr, Herron, Dijk, & Ellis, 2008) and fatigue that qualitatively differs from "normal" feelings of fatigue they experienced prestroke (De Doncker, Dantzer, Ormstad, & Kuppuswamy, 2018). Speech-language pathologists frequently observe signs of fatigue in their clients with aphasia and perceive that client fatigue impedes therapeutic interventions (Riley, 2017). The current study aimed to quantify daytime sleepiness, exertion fatigue, and physiologically measured arousal and vigilant attention in persons with aphasia. Method We measured sleepiness, exertion fatigue, arousal, and vigilant attention in 10 participants with aphasia and 10 neurologically healthy adults. Daytime sleepiness was measured using the Epworth Sleepiness Scale (Johns, 1991). Exertion fatigue was measured using the Visual Analog Fatigue Scale (B. Y. Tseng, Gajewski, & Kluding, 2010) before and after a 72-min computer-administered language task. Arousal was measured using heart rate and variability (Shaffer & Ginsberg, 2017). Vigilant attention was measured using electroencephalography and subsequently classified into 1 of 4 levels of vigilant attention using a classification algorithm (Berka et al., 2004). Results Persons with aphasia did not show significant differences from controls in reported amount of daytime sleepiness, exertion fatigue, or overall physiological arousal but demonstrated different patterns of electroencephalography-measured vigilant attention and error production as compared to controls. Conclusions Although overall sleepiness, exertion fatigue, and overall arousal did not differ between groups, physiological measures of vigilant attention may be more sensitive to differences and may explain feelings of fatigue that persons with chronic aphasia experience.