Potassium-ion batteries (PIBs) are considered as promising alternatives to lithium-ion batteries due to the abundant potassium resources in the Earth’s crust. Establishing high-performance anode materials for PIBs is essential to the development of PIBs. Recently, significant research effort has been devoted to developing novel anode materials for PIBs. Alloy-based anode materials that undergo alloying reactions and feature combined conversion and alloying reactions are attractive candidates due to their high theoretical capacities. In this review, the current understanding of the mechanisms of alloy-based anode materials for PIBs is presented. The modification strategies and recent research progress of alloy-based anodes and their composites for potassium storage are summarized and discussed. The corresponding challenges and future perspectives of these materials are also proposed.