<p>MXenes, a novel class of 2D transition metal carbides, nitrides and carbonitrides have garnered extensive interest due to their layered structure. MXene is synthesised from MAX phases by various methods such as etching, hydrothermal approach, chemical vapor deposition, ball milling etc. Characteristic of MXene is greatly influenced by the method adopted for its synthesis and hence synthesis method should be selected based on the intended applications. Recently, MXenes gain more attention as effective fillers for developing flame retardant polymer composites due to the presence of various functional groups. The flammability of polymers is a critical issue that limits its potential usage in various industrial applications. The excessive heat generation and fire risks leads to degradation and failure of the polymer component. Hence, it is crucial to improve flame retardancy and thermal conductivity of polymers to ensure its safe operation and to avoid a firetrap. Incorporation of MXene in polymers not only improves the flame-retardant properties but also increases the mechanical and thermal stability. Addition of MXene in epoxy and polyurethane based matrix leads to decrease in heat release rate and increase in the char yield percentage. This review brings a comprehensive outline of the MXene synthesis techniques along with thermal and flammability properties of MXene-polymer composites.</p>