COVID-19 has a profound impact on the mental health of healthcare workers, especially those combatting the disease. The current study examined the mediating role of psychological capital in the relationship between fear of COVID-19 and intolerance of uncertainty and positive future expectations in healthcare workers during the pandemic. 310 healthcare workers (51.9 % males, M age = 34.2 ± 7.6) completed measures of fear of COVID-19, psychological capital, intolerance of uncertainty, and positive future expectations The results showed that fear of COVID-19 had a significant negative predictive impact on psychological capital and a significant positive predictive impact on intolerance of uncertainty. Psychological capital had a significant negative predictive impact on intolerance of uncertainty and a significant positive predictive impact on positive future expectations. Most importantly, the results indicated that psychological capital mediated the association of fear of COVID-19 with intolerance of uncertainty and positive future expectations. The results improve our understanding of the role of psychological capital in the relationship between fear of COVID-19 and intolerance of uncertainty and positive future expectations. Also, results have possible wider implications for equipping healthcare workers with the psychological tools to cope with stressors, including those linked to public health threats such as pandemics.