Potassium-ion　batteries　are　among　the　most　promising　candidates　to　satisfy　the　large-scale　energy　storage　systems　due　to　their　low-cost　and　abundant　potassium　sources.　However,　it　is　highly　desired　to　seek　suitable　cathode　materials　with　high　capacity　and　voltage　platform,　long　cycling　stability　and　durability.　Transitional　metal　layered　oxides　as　the　most　important　cathode　materials　have　been　widely　investigated　in　lithium-ion　batteries　and　sodium-ion　batteries.　Recently,　transitional　metal　layered　oxides　for　potassium-ion　batteries　have　aroused　huge　attention　owing　to　their　special　structures　and　potential　in　applications.　Although　most　transitional　metal　layered　oxides　exhibit　tolerable　capacities,　the　relationship　between　structure　and　electrochemical　performance　needs　further　investigation　in　detail.　Herein,　the　research　status　and　development　of　transitional　metal　layered　oxides　for　potassium-ion　batteries　are　summarized　in　this　review.　To　solve　the　existing　problems　of　transitional　metal　layered　oxides　in　potassium-ion　batteries,　the　improvement　of　air　stability　and　electrochemical　performance　are　also　thoroughly　discussed.　Based　on　the　achievements　in　recent　years,　a　prospect　on　the　further　development　of　transitional　metal　layered　oxides　for　potassium-ion　batteries　is　also　provided.　©　2020