Background: Despite the indisputable negative psychosocial consequences of the COVID-19 pandemic (e.g., posttraumatic stress disorder), positive ones (i.e., posttraumatic growth) are also possible. Although resilience and coping strategies have been assumed to contribute to these outcomes, findings are still scarce and inconclusive. Aim: The study aimed to examine the role of resilience and coping strategies in the positive and negative posttraumatic outcomes of the COVID-19 lockdown among the Greek general public (GP) and healthcare workers (HCWs). Materials and Methods: A sample of 1661 participants (986 GP and 673 HCWs), coming from Greece were recruited. A google-forms questionnaire was distributed during April 5-30, 2000 through social networking sites, webpages, and personal contacts of the author amid the lockdown (March 23-May 03). Sociodemographic data were collected. Measures of posttraumatic stress symptoms, posttraumatic growth, resilience, and coping strategies were also administered. Results. Regression analyses demonstrated that resilience and coping strategies were differentially associated with post-trauma outcomes. Resilience and mostly maladaptive coping strategies predicted PTSD and STS. A mixture of adaptive and maladaptive coping strategies predicted PTG for both subgroups. PTSD for the GP and resilience for the HCWs also predicted PTG. Conclusions and implications. The findings contribute to a more comprehensive understanding of the coping strategies used by different population subgroups in dealing with the COVID-19 lockdown in Greece. Enhancing internal resources through supportive services will ameliorate populations’ ability to withstand, recover, and thrive with benefits in their psychological health and well-being.