Though not always immediately recognizable, fatigue and tiredness play a central role in modernist literature. As society placed increasing value on productive, strong, energetic bodies, the growing presence of bodies tired from the effects of overwork, rapid social progress, illness and post-war malaise posed a threat both to society and ideas of the able-bodied self. Recumbent bodies challenge expectations of productivity; they remindus of our own bodily fallibility and blur the line between life and death as a visual representation of our own mortality. Further, the fatigued body at rest is predominantly associated with the feminine, as has been reflected in much prior academic engagement with neurasthenic women in modernist literature. What then are the implications for fatigued men? This thesis traces the previously overlooked depictions and uses of fatigue in two texts that have been the subject of significant analysis: The Metamorphosis by Franz Kafka and At Swim-Two-Birds by Flann O’Brien. Though neither of these texts are inherently medical in nature, I show how fatigue nonetheless plays a central role in each, albeit in quite different ways. By unpacking these contrasting engagements with fatigue and the simultaneous lack of critical interest in fatigue in these texts, I uncover stigmatizing social perceptions of fatigue as deviant, burdensome, and indicative of emasculating weakness. Further, such depictions seem to go unquestioned, suggesting that these beliefs are largely naturalized within Western society. In the current time of pandemic, as society is again increasingly confronted with very visible exhaustion in the form of Long Covid amongst other fatiguing conditions, modernist fiction from the early-twentieth century offers valuable insights into how we engage with fatigue.