["Autism Research, EarlyView. ", "\nABSTRACT\nAuditory mismatch responses—mismatch negativity (MMN) and mismatch fields (MMF)—are well established electrophysiological markers of automatic auditory discrimination supported by short‐term sensory memory. These responses, typically elicited using passive oddball paradigms, are increasingly used to investigate sensory and language processing in autism. This systematic review synthesizes findings from 55 studies comparing MMN and MMF responses in autistic and typically developing (TD) individuals across childhood, adolescence, and adulthood. Using the Synthesis Without Meta‐analysis (SWiM) framework, we identified consistent evidence for smaller MMN amplitudes and reduced MMF power in autistic children and adolescents relative to TD peers, particularly in response to frequency, duration, and speech‐based deviants. Studies also frequently reported longer mismatch latencies in autistic participants and associated these delays with language difficulties and heightened auditory sensitivity. Although some studies reported age‐related convergence in MMN and MMF measures between autistic and TD groups in later childhood or adolescence, greater right‐hemisphere lateralization in autistic individuals emerged as a consistent finding across both speech and non‐speech paradigms, suggesting differences in hemispheric weighting for auditory processing of linguistic and non‐linguistic cues. To explain interindividual and developmental variability in mismatch responses, we propose a precision‐weighted predictive coding account, in which divergent assignment of confidence to sensory prediction errors may contribute to autism‐related differences. While study quality was generally fair, methodological heterogeneity, underrepresentation of females, and limited cross‐cultural sampling constrain generalizability. Future research should prioritize longitudinal, sex‐stratified, and culturally diverse designs, using standardized protocols and collaborative data practices. MMN and MMF responses hold promise as non‐invasive translational biomarkers of early‐stage sensory prediction and neurodevelopmental variation in autism.\n"]