Iron oxides, such as Fe2O3 and Fe3O4, have recently received increased attention as very promising anode materials for rechargeable lithium-ion batteries (LIBs) because of their high theoretical capacity, non-toxicity, low cost, and improved safety. Nanostructure engineering has been demonstrated as an effective approach to improve the electrochemical performance of electrode materials. Here, recent research progress in the rational design and synthesis of diverse iron oxide-based nanomaterials and their lithium storage performance for LIBs, including 1D nanowires/rods, 2D nanosheets/flakes, 3D porous/hierarchical architectures, various hollow structures, and hybrid nanostructures of iron oxides and carbon (including amorphous carbon, carbon nanotubes, and graphene). By focusing on synthesis strategies for various iron-oxide-based nanostructures and the impacts of nanostructuring on their electrochemical performance, novel approaches to the construction of iron-oxide-based nanostructures are highlighted and the importance of proper structural and compositional engineering that leads to improved physical/chemical properties of iron oxides for efficient electrochemical energy storage is stressed. Iron-oxide-based nanomaterials stand a good chance as negative electrodes for next generation LIBs.