We hypothesize and provide empirical evidence that higher institutional investor inattention is associated with lower audit quality. We employ an inattention measure that captures the extent to which institutional investors are distracted by attention-grabbing events irrelevant to the focal firm. Results suggest that a higher degree of institutional investor inattention is associated with a lower propensity of a going-concern opinion, a lower probability of the auditor reporting a material internal control weakness, and a higher likelihood of the audit client misstating the financial statements. Further analyses show that these associations vary by auditor litigation risk, their workload pressure, auditor industry expertise, and analyst coverage. Overall, our findings reveal that while institutional investors play an important monitoring role, the distractions they face undermine the quality of monitoring they provide.