The COVID-19 pandemic has created a global health emergency and has a huge impact on the health care workers, especially on their mental health. The dataset presented was an assessment of COVID-19 related knowledge, attitude, practices and its effects on the mental health of frontline healthcare workers in Pakistan. The data were collected using a snowball sampling technique. A questionnaire was developed assessing sociodemographic characteristics (6 items), knowledge (11 items), attitude (5 items), practices (6 items), information sources (1 item) and psychological implications (12 items) and distributed using online tools. The dataset includes 476 healthcare workers in Pakistan. The dataset will help to prevent and curb the spread of COVID-19 among health workers and contribute to policymakers. Furthermore, our dataset provides detailed insights into different risk factors of psychological problems, and it may be served as the reference for various in-depth surveys.