Background: Due to the current coronavirus (COVID-19) crisis, workplaces have had to make significant alterations in the way they conduct business. This, in addition to the current financial instability, may put workers at risk of experiencing job insecurity and, in turn, lower wellbeing. Job insecurity is a key determinant of wellbeing, but little is known on how it is impacted by public health crises, and more specifically how it relates to workers’ positive and negative wellbeing in the midst of a pandemic. Research is lacking on resilience levers that workplace interventions should target to support wellbeing in times of insecurity. Objective: Framed from a multidisciplinary perspective (public health, positive and organizational psychology), the study explores (1) workers’ job (in)security during the COVID-19 pandemic one to two weeks after social distancing measures were implemented by Canadian governments, (2) how job (in)security relates to wellbeing during the pandemic, and (3) the potential positive effects of workplace-related resilience levers. Method: 1,073 Canadian workers working full-/part-time or who were temporarily laid off completed an online survey, including measures of wellbeing at work or in general, job security and potential resilience levers (workplace disaster preparedness, policy, social capital). Results: Multiple regression findings highlight that marginalized workers (e.g., women, migrants, people facing financial hardships) reported lower job security, and having temporarily lost one’s job was negatively associated with job security. Low job security was related to lower scores across measures of wellbeing. Distress was high in the sample. Workplace disaster preparedness, policy and social capital were associated with higher wellbeing. The effects of these resilience levers tended to be stronger at higher job security levels. Discussion: Recommendations include a systemic, collaborative approach that includes policies fostering job security as well as resilience-promoting interventions in the workplace to protect/increase the wellbeing of workers during COVID-19. © 2020, International Journal of Wellbeing Charitable Trust. All rights reserved.