Solid　polymer　electrolytes　(SPEs)　for　lithium　metal　batteries　have　garnered　considerable　interests　owing　to　their　low　cost,　flexibility,　lightweight,　and　favorable　interfacial　compatibility　with　battery　electrodes.　Their　soft　mechanical　nature　compared　to　solid　inorganic　electrolytes　give　them　a　large　advantage　to　be　used　in　low　pressure　solid-state　lithium　metal　batteries,　which　can　avoid　the　cost　and　weight　of　the　pressure　cages.　However,　the　application　of　SPEs　is　hindered　by　their　relatively　low　ionic　conductivity.　In　addressing　this　limitation,　enormous　efforts　are　devoted　to　the　experimental　investigation　and　theoretical　calculations/simulation　of　new　polymer　classes.　Recently,　metal–organic　frameworks　(MOFs)　have　been　shown　to　be　effective　in　enhancing　ion　transport　in　SPEs.　However,　the　mechanisms　in　enhancing　Li+　conductivity　have　rarely　been　systematically　and　comprehensively　analyzed.　Therefore,　this　review　provides　an　in-depth　summary　of　the　mechanisms　of　MOF-enhanced　Li+　transport　in　MOF-based　solid　polymer　electrolytes　(MSPEs)　in　terms　of　polymer,　MOF,　MOF/polymer　interface,　and　solid　electrolyte　interface　aspects,　respectively.　Moreover,　the　understanding　of　Li+　conduction　mechanisms　through　employing　advanced　characterization　tools,　theoretical　calculations,　and　simulations　are　also　reviewed　in　this　review.　Finally,　the　main　challenges　in　developing　MSPEs　are　deeply　analyzed　and　the　corresponding　future　research　directions　are　also　proposed.　©　2024　Wiley-VCH　GmbH.