The oxygen evolution reaction (OER) is involved in various renewable energy systems, such as water‐splitting cells and metal–air batteries. Ni‐Fe layered double hydroxides (LDHs) have been reported as promising OER electrocatalysts in alkaline electrolytes. The rational design of advanced nanostructures for Ni‐Fe LDHs is highly desirable to optimize their electrocatalytic performance. Herein, we report a facile self‐templated strategy for the synthesis of novel hierarchical hollow nanoprisms composed of ultrathin Ni‐Fe LDH nanosheets. Tetragonal nanoprisms of nickel precursors were first synthesized as the self‐sacrificing template. Afterwards, these Ni precursors were consumed during the hydrolysis of iron(II) sulfate for the simultaneous growth of a layer of Ni‐Fe LDH nanosheets on the surface. The resultant Ni‐Fe LDH hollow prisms with large surface areas manifest high electrocatalytic activity towards the OER with low overpotential, small Tafel slope, and remarkable stability. A self‐templated strategy enables the synthesis of hierarchical hollow nanoprisms composed of ultrathin Ni‐Fe layered double hydroxide (LDH) nanosheets. During the hydrolysis of iron(II) sulfate, prism‐like Ni precursors are dissolved and converted into a shell of Ni‐Fe LDH on their surface. Owing to structural and compositional advantages, these hollow nanoprisms display enhanced electrochemical activity in the oxygen evolution reaction.