Purpose: COVID-19 pandemic has created a serious psychological impact worldwide since it has been declared. This study aims to investigate the level of psychological impacts of COVID-19 pandemic on Turkish population and to determine related factors. Methods: The study was carried out by using an online questionnaire using the virtual snowball sampling method. The sociodemographic data were collected on the following subjects: Participants’ experience on any signs of infection within the last month, the history of COVID-19 contact-treatment-quarantine, level of compliance with precautionary measures, the sources of information and level of knowledge about the pandemic process and their belief levels on the knowledge they acquire. Besides, questions that take place in the depression, anxiety, stress scale (DASS-21), and impact of events scale (IESR) were asked. Results: Of the 3549 participants, anxiety was found in 15.8%, depression in 22.6%, stress in 12.9%, and psychological trauma in 20.29%. Female gender, young age, higher education level, being single, high monthly income, presence of psychiatric illness, a high number of people living together, having any signs of infection, and contact history with COVID-19 infected person or contaminated object are identified as risk factors that may increase psychological impact. Compliance with the rules was found to reduce the risk of psychological response. Conclusions: During the pandemic, reducing the spread of the virus and knowing the risk factors in protecting the mental health of individuals will be guided in determining the measures to be followed and the policies to be followed.