MXene is a novel 2D nanomaterial with excellent mechanical properties, thermal and electrical conductivities, flame retardancy, electromagnetic interference shielding, etc. Owing to these inherent properties, MXene is extensively used as a reinforcing and functional material in elastomer nanocomposites while identifying its capabilities and potential applications. Due to the above reasons, a systematic and rationally well-detailed up-to-date review focused on an overall understanding of MXene/elastomer nanocomposites is needed. Hence, a critical review is provided herein, reporting the status of research on MXene/elastomer nanocomposites, knowledge gaps, and future potential. A bibliometric analysis shows a steady growth of research interest in MXene/elastomer nanocomposites. Also, metadata on reported synthesis processes and pre-surface modifications of MXene indicate the parameters and fine-tuned functionalities of MXene in nanocomposites. The characterization of MXene/elastomer nanocomposites is critically reviewed, focusing on mechanical properties, electrical and thermal conductivities, photothermal and electrothermal conversion, and flame resistance. Finally, the applications of these composites, e.g., electromagnetic interference shielding, sensing, and energy applications, have also been reviewed, emphasizing the existing technical challenges and possible future directions in the field.