Background COVID-19 is a novel event of the twenty-first century. Therefore, contemporary research is required to determine the current pandemic's psychological impact on older populations. Soon after the COVID-19 outbreak, several narrative reviews and guidelines were released to support older adult's psychological wellbeing. However, a lack of data from original studies was reported until May 2020. Aim To identify studies published from May 2020 until January 2021 that quantitatively assessed the mental health impact of COVID-19 on older adults using validated psychometric tools. Method A comprehensive literature search of original research articles was conducted using specific terms. The screening procedure was conducted stepwise. Results Among the 18 included studies, cross-sectional online surveys indicated that older adults were less psychologically distressed than younger ones. A longitudinal study revealed that COVID-19 did not have a major impact on loneliness and satisfaction with life. On the contrary, studies comparing pre-with peri-pandemic data revealed that older adults experienced more severe depressive/anxiety/stress symptoms and loneliness during the pandemic. Several studies reported though only subclinical symptoms, as well as low loneliness levels during the pandemic. Conclusions Research studies suggested that older age may buffer against the COVID-19-related impact on mental health. Despite evidence against generalised perceptions of vulnerability, older adults' ability to adapt to adversity may be uneven, depending on cultural, social, economic and other individual factors. Taken together, the impact, moreover the long-term impact of COVID-19, is expected to vary across countries and older subpopulations, and remains to be evaluated by prospective, longitudinal studies.