Introduction: The ongoing multi-country outbreak of monkeypox (MPX) that emerges in non-endemic areas is a rare and unprecedented event that ignited a widespread public health concern. So far, Lebanon has reported four confirmed cases of MPX. Since good knowledge about the MPX virus and its associated disease is paramount for helping the Lebanese population prepare for a possible outbreak, therefore, it is important to assess their current level of knowledge regarding MPX and to identify its associated factors to highlight gaps in knowledge that should be filled.Methods: An online cross-sectional study was conducted over the first two weeks of August 2022 among adults aged 18 years and above recruited from all Lebanese provinces using a convenience sampling technique. An anonymous, Arabic, self-reported questionnaire covering all main aspects of knowledge regarding MPX was developed and adapted based on the available literature. Multivariable logistic regression was performed to identify the factors associated with knowledge level.Results: A total of 793 Lebanese adults participated in the study. The overall level of knowledge level regarding human MPX was poor among the Lebanese population; with only 33.04% of them having a good knowledge level ≥60%. Knowledge gaps and a substantial poor knowledge level were found in the majority of MPX knowledge domains especially those related to the routes of transmission (76.67%), clinical presentation and symptoms (71.63%), treatment (86.25%), and severity of the disease (91.3%). Interestingly, participants have a good knowledge level of the precautionary measures (80.45%), and the response to a suspected infection (65.20%). Female gender, increased age, and living in rural areas were found negatively associated with a good level of knowledge. However, participants with higher educational levels, those working in the medical field, those suffering from chronic disease/immunodeficiency, and participants with moderate/high economic situations were more likely to have a good knowledge score compared to their counterparts.Conclusion: The current study pointed out to poor knowledge level regarding MPX among the Lebanese population with substantial knowledge gaps in the majority of aspects of MPX knowledge. Our findings stress the urgent need to raise awareness and proactively fill the unveiled gaps, especially among less informed groups.