Multiple sclerosis is a chronic autoimmune disease that progresses over time, leading to disability. The condition is still incurable, but available therapies are increasingly effective. Ocrelizumab is the first anti-CD20 monoclonal antibody approved for the treatment of relapsing-remitting and primary progressive forms of multiple sclerosis. In the article, based on the results of the OPERA and ORATORIO clinical trials, their extensions, and post-hoc and meta-analyses, the evidence for long-term high effectiveness of the molecule is presented. Aspects including the control of relapses (annual relapse rate and time to relapse), delay in the occurrence of confirmed disability, probability to achieve disability improvement, need to use a wheelchair and loss of upper limb mobility, as well as radiological activity (gadolinium-enhancing lesions, new T2 lesions, brain atrophy), are assessed. An additional advantage of the OPERA studies is that almost similar results, acquired with identical protocols in a different patient populations, were achieved. Moreover, the effects of therapy did not wear off over time. Based on these findings, ocrelizumab can be regarded as a highly effective therapy in multiple sclerosis, with the highest (48%) NEDA-3 index (no evidence of disease activity) and the greatest potential for delaying the onset of confirmed disability. The presented studies also confirm the benefit of introducing the drug in multiple sclerosis therapy as early as possible.