The recent COVID-19 pandemic has imposed threats on both physical andmental health since its outbreak. This study aimed to explore the impactof the COVID-19 pandemic on mental health among a representativesample of home-quarantined Bangladeshi adults. A cross-sectional designwas used with an online survey completed by a convenience samplerecruited via social media. A total of 1,427 respondents were recruited,and their mental health was assessed by the DASS-21 measure. Theprevalence of anxiety symptoms and depressive symptoms was 33.7%and 57.9%, respectively, and 59.7% reported mild to extremely severelevels of stress. Perceptions that the pandemic disrupted life events,affected mental health, jobs, the economy and education, predictions ofa worsening situation, and uncertainty of the health care system capacitieswere significantly associated with poor mental health outcomes.Multivariate logistic regressions showed that sociodemographic factorsand perceptions of COVID-19 significantly predict mental health outcomes.These findings warrant the consideration of easily accessible lowintensitymental health interventions during and beyond this pandemic.