This paper is an empirical investigation that examines a path model linking COVID-19 perceptions to organisational citizenship behaviour (OCBs) via three mediators: job insecurity, burnout, and job satisfaction. The research examines the path model invariance spanning Generations X, Y, and Z. Three countries in the Middle East and North Africa (MENA) were the focus of the study. The data was collected from a sample of employees in service companies. We used a Partial Least Square Structural Equation Modelling (PLS-SEM) to analyse the data. Our findings reveal that COVID-19 positively predicts job insecurity, which positively impacts burnout levels. Burnout negatively predicts job satisfaction. The findings established that job satisfaction positively predicts OCBs. The mediation analysis determined that job insecurity, burnout and job satisfaction convey the indirect effects of COVID-19 perceptions onto OCBs. However, our multi-group analysis revealed that the indirect effects of COVID-19 on OCBs were only valid amongst younger generations, i.e., Generation Y and Generation Z. Finally, our hypothesised model is not invariant across Generations X, Y and Z. Specifically, younger generations are substantially more vulnerable to the indirect effects of COVID-19 perceptions on their engagement in OCBs than Generation X whose job satisfaction blocks the effects of COVID-19 perceptions on OCBs.