Background: The COVID-19 pandemic has led to prolonged exposure to stress and anxiety, raising concerns about a large spectrum of psychological side effects. The primary objective of the study was to validate the COVID-19 Bullying Scale (CBS-11). The second objective was to explore factors associated with COVID-19-related bullying and evaluate the mediating effect of fear and anxiety between knowledge and COVID-19-related bullying.Methods: A cross-sectional online survey conducted between December 20, 2020, and January 5, 2021, involved 405 Lebanese adults recruited using the snowball sampling technique. The CBS-11, an 11-item tool specially created for this study, was used to measure bullying behaviors towards COVID-19 patients.Results: All items of CBS-11 converged over a 1-factor solution with an eigenvalue over 1, accounting for a variance of 75.16%. The scale has a high Cronbach’s alpha (0.974), indicating excellent reliability. A positive correlation was found between the COVID-19 bullying scale and fear, anxiety, and stigma discrimination. The logistic regression showed that higher fear of COVID-19 (ORa=1.04), a positive attitude toward COVID-19 preventive measures and hygiene recommendations (ORa=1.18), higher stigma discrimination scores (ORa=1.09), and having a health professional family member (ORa=2.42) were significantly associated with bullying. Conclusion: Our main findings show that CBS-11 could be an efficient tool to measure bullying behaviors toward COVID-19 patients. Stigma discrimination and fear from COVID-19 were associated with higher bullying attitudes. Future prospective studies are needed to understand better the factors related to bullying among adults during a pandemic, such as COVID-19.