The objective of this systematic review was to examine the technical and diagnostic capability of magnetic resonance imaging (MRI) to identify carpal tunnel syndrome (CTS). Two independent authors retrieved and screened the existing data and extracted the clinical and validity data adhering to predefined inclusion criteria. The MRI methods and findings were analyzed by two experienced radiologists. Disagreements were solved in consensus. The MRI findings of 373 affected wrists in 13 studies were compared with asymptomatic referents or a series of patients with non-CTS wrist pain. Increased T2-signal, cross-sectional area, and flattening of the median nerve inside the carpal tunnel, as well as bowing of the flexor retinaculum, were the most frequently occurring signs in CTS. Reliable assessment of the sensitivity and specificity of certain MRI signs in respect to CTS remained difficult due to study heterogeneity. There is an obvious need for imaging studies in which validated diagnostic criteria are used.