OBJECTIVE: This study aims to assess and compare demographic and psychological factors and sleep status of frontline HCWs in relation to non-frontline HCWs DESIGN, SETTINGS, AND PARTICIPANTS This cross-sectional study was conducted using an online survey from the 8th to the 17th of April 2020 across varied health care settings in Oman accruing 1139 HCWS. MAIN OUTCOMES AND MEASURES Mental health status was assessed using Depression, Anxiety HP, and Stress Scales (DASS-21), and insomnia HP was evaluated by the Insomnia HP Severity Index (ISI). Samples were categorized into the frontline and non-frontline groups. Chi-square, odds ratio, and independent t-tests were used to compare groups by demographic and mental health outcomes. Results This study included 1139 HCWs working in Oman. There was a total of 368 (32.3%), 388 (34.1%), 271 (23.8%), and 211 (18.5%) respondents reported to have depression, anxiety HP, stress, and insomnia HP, respectively while working during the pandemic period. HCWs in the frontline group were 1.4 times more likely to have anxiety HP (OR=1.401, p=0.007) and stress (OR=1.404, p=0.015) as compared to those working in the non-frontline group. On indices of sleep-wake cycles, HCWs in the frontline group were 1.37 times more likely to report insomnia HP (OR=1.377, p=0.037) when compared to those working in the non-frontline group. No significant differences in depression status between workers in the frontline and non-frontline groups were found (p=0.181). CONCLUSIONS AND RELEVANCE To our knowledge, this is the first study to explore the differential impacts of the COVID-19 pandemic on different grades of HCWs. This study suggests that frontline HCWs are disproportionally affected compared to non-frontline HCWs. The problem with managing sleep-wake cycles and anxiety HP symptoms were highly endorsed among frontline HCWs. As psychosocial interventions are likely to be constrained owing to the pandemic, mental health care must first be directed to frontline HCWs.