This systematic review and meta-analysis was conducted in accordance with PRISMA guidelines to explore diagnostic errors in peripheral facial palsy in adults and their impact on medical and paramedical care. Four databases were used to collect 303 articles, 23 of which, published between 2015 and 2024, were analyzed using the CARE grid for case studies and the JBI grid for case series. Fifty cases of diagnostic error were identified. A tumor was found to be the cause in 56% of cases that were initially identified as Bell's palsy. The results of this meta-analysis show that symptoms that come on gradually are linked to longer time to diagnosis ( P = 0.04). Furthermore, time to diagnosis was significantly longer ( P = 0.04) when the final diagnosis was a tumor. The results also highlight the importance of detailed clinical and medical assessment, particularly for women, who are consistently diagnosed later than men despite presenting the same symptoms. The challenge of diagnosis by exclusion is highlighted by the diversity of etiologies, but is essential before a diagnosis of Bell's palsy can be established. Healthcare professionals must be vigilant in case of atypical developments in peripheral facial palsy, as such cases can be complex and require careful monitoring. Paramedical professionals also play a key role in alerting the medical profession when the progression of the disorder does not correspond to the typical clinical picture.