Objectives: The purpose of this study was to investigate Ontario adults' reported sleep quantity, quality, and disturbances during the early months of the COVID-19 pandemic (April–July 2020). Methods: As part of a larger, chronic disease-focused, and ongoing longitudinal study designed to explore Ontario adults' health and wellness-related behaviors during the pandemic, participants completed an online survey that included demographic information and the Pittsburgh Sleep Quality Index (PSQI). The PSQI consists of 19 items, one of which is open-ended, designed to assess an individual's quantity, quality, and patterns of sleep on seven domains (ie, subjective sleep quality, sleep latency, sleep duration, habitual sleep efficiency, sleep disturbances, use of sleep medication, and daytime dysfunction over the last month). Summative content analysis was used to analyze responses to the open-ended question regarding participants' sleep disturbances. Results: This study included 2192 individuals, 85% of whom slept 6+ hours/night. The mean global PSQI score was 7.57, out of a possible 21 (SD = 4.09). The self-reported sleep disturbances of largest concern were: (1) general fear/anxiety/worry (n = 203); (2) children (n = 167); (3) mind wandering/overthinking (n = 118); (4) pain/injury (n = 78); (5) partner (n = 78); and (6) fear/anxiety/stress related to COVID-19 (n = 74). Conclusion: The global PSQI score was indicative of poor sleep quality, and Ontario adults experienced a number of sleep disturbances during early days of the COVID-19 pandemic. These findings are noteworthy as sleep is a crucial component in positive health and wellbeing.