OBJECTIVE: Many previously reported publications mentioned that oral lesion in COVID-19 patients was varied. The term oral manifestations refer to pathognomonic features that are found consistently with a specific cause and effect. In this context, the oral manifestation of COVID-19 was inconclusive. This systematic review aimed to analyse previously reported publications related to oral lesions in COVID-19 patients to define as oral manifestations or not. The PRISMA guidelines were implemented in this review. METHODS: All umbrella reviews, systematic reviews, systematic reviews and meta-analyses, comprehensive reviews, and original and non-original studies were included. Twenty-one of systematic review, 32 original studies and 68 non-original studies reported the oral lesion in COVID-19 patients. RESULTS: Most of the publications mentioned that ulcers, macular, pseudomembranes and crusts were frequent oral lesions. The reported oral lesions in COVID-19 patients did not show any pathognomonic features and might be unrelated directly to COVID-19 infections, however, more likely due to gender, age, underlying diseases, and medication. CONCLUSION: The oral lesions found in previous studies do not have pathognomonic features and are inconsistent. Therefore, the reported oral lesion, in present time, cannot be defined as an oral manifestation.