Objectives: This study examined the mediation role of fear of COVID-19 in the association between perceived health status of older adults and their insomnia, mental health, and COVID-19 preventive behaviors so as to have better understanding of the factors associated with COVID-19 and its preventive measures. Methods: A total of 413 older adults with a mean age of 57.72 (SD = 7.31) were recruited for this study. They responded to the measures on fear of COVID-19, insomnia, mental health, and COVID-19 preventive behaviors. Results: There were small-large significant interrelationships between insomnia, mental health, fear of COVID-19, and preventive behaviors. Fear of COVID-19 significantly mediated the associations between perceived health status and insomnia, mental health, and COVID-19 preventive behaviors. It was also observed that perceived health status directly influenced insomnia and mental health of older adults but not their COVID-19 preventive behaviors. Conclusion: Fear of COVID-19 has an important role to play in the management of the health and preventive behaviors of older adults. Health experts and communicators may capitalize on these findings to educate people on COVID-19. Future studies are needed to perfectly ascertain the extent of fear needed to stimulate or initiate better preventive behaviors and healthcare practices.