The COVID-19 has been spreading across the world since December 2019. The pandemic has created tremendous fear of death from infection and awful psychological pressure on healthcare professionals (HCPs). The measures of psychological effects of the COVID-19 outbreak on the Bangladeshi HCPs are unknown. The present study aimed to assess the mental health outcomes of Bangladeshi HCPs and associated risk factors. We conducted this cross-sectional study from July 15 to September 20, 2020. A total of 355 HCPs aged between 20 and 60 years residing in Bangladesh participated in this study. All the participants completed a self-administered questionnaire through Google Forms consisting of socio-demographic characteristics and mental health outcomes. We measure loneliness, depression, anxiety, and sleep disturbance using the UCLA loneliness scale-8, patient health questionnaire-9, 7-item generalized anxiety disorder scale, Pittsburgh sleep quality index. The present study observed the prevalence of loneliness, depression, anxiety, and sleep disturbance among HCPs were 89%, 44%, 78%, and 87%, respectively. The factors significantly associated with the development of mental health problems among HCPs were working environment, economic condition, education level, area of residence, marital status, gender differences, professional category, body mass index, and smoking habit. Moreover, we have seen significant correlations among the different mental health outcomes. In Bangladesh, a large portion of HCPs reported mental health issues during the COVID-19 pandemic. COVID-19 pandemic incredibly impacted the psychological health of Bangladeshi healthcare professionals. Appropriate supportive programs and interventional initiatives might help the HCPs with mental health problems during and after this pandemic.