Objective To determine factors that contribute to delayed diagnosis and treatment of MS patients. Additionally, the study aimed to evaluate the correlation between diagnostic and therapeutic delay and disease outcome. Methods The current cohort observational multicenter study was performed at neurology clinics in four cities in Egypt. In this study, 239 MS patients were enrolled. Multiple Sclerosis Severity Scale (MSSS) and Expanded Disability Status Scale (EDSS) were utilized to measure disease severity and disability, respectively. Lag times for diagnosis were calculated in months from the time of the first symptoms to the accurate diagnosis. Results The results revealed that multiple important variables had a negative impact on the timely diagnosis, including the clinical type, as PPMS had longer delayed diagnoses versus RRMS/SPMS (p < 0.001). Conversely, the occurrence of sensory symptoms at disease onset is linked to prolonged diagnostic delay (p < 0.001). Multivariate logistic regression showed that young age, PPMS, and sensory symptoms were independently associated with delay in MS diagnosis. Patients initially sought medical assistance from ophthalmologists and neurologists, resulting in a significantly more delay in diagnosis (p < 0.001). A statistically positive correlation exists between the time for diagnosis and deterioration of MS assessed by EDSS, MSSS, or PI (p < 0.001). In addition, logistic regression analysis demonstrated that EDSS at diagnosis, delayed diagnosis, and illness duration were independently linked to MS severity (p < 0.001). Conclusion Many factors prolong the duration of MS diagnosis, including the age at disease onset, the delay in being referred from other medical specialties, and the presence of sensory symptoms at disease onset. Furthermore, MS delayed diagnosis and treatment leads to high disease disability with poor functional outcomes