MRI plays an increasingly important role in the diagnosis of multiple sclerosis. We discuss the expanded role of MRI in the 2024 McDonald diagnostic criteria for multiple sclerosis, which include the optic nerve as a fifth anatomical location, in addition to the periventricular, juxtacortical or cortical, infratentorial, and spinal cord regions. The diagnosis of multiple sclerosis can now be confirmed when the criteria of dissemination in space are fulfilled with the detection of typical lesions in at least four locations without additional evidence. We recommend appropriate imaging strategies and MRI acquisition protocols for all aspects of multiple sclerosis diagnosis, including fat-saturated sequences for detection of symptomatic optic nerve lesions. Diagnostic imaging should always cover the brain and spinal cord and include susceptibility-sensitive sequences for the assessment of the central vein sign and paramagnetic rim lesions, which can be especially helpful in cases when conventional imaging findings are insufficient to establish a diagnosis. We discuss how to handle the diagnosis of radiologically isolated presentations of multiple sclerosis, which are included in the 2024 criteria. We present recommendations for image interpretation and avoidance of misdiagnosis, and extend the recommendations to the use of MRI in the diagnosis of multiple sclerosis in older people, children, people with vascular comorbidities or migraine, and people living outside Europe and North America. Finally, we provide recommendations for standardisation of MRI acquisition and communication of results to enable an earlier diagnosis while maintaining high diagnostic specificity.