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In this study, we demonstrated the temperature effect of our previously developed topotatic catalysis for the formation of Mn0.005Co2.995O4(MnCoO) spinel nanoparticles. Topotatic catalysis induces spinel MnCoO nanoparticles through the redox reaction of the metal cation (Co2+and Mn2+) on the Co(OH)2nanosheet surface, acting as a growth template. This study particularly elucidates the temperature effect on spinel MnCoO nanoparticles' size, morphology, and crystallinity based on their electrocatalytic performance in an oxygen reduction reaction (ORR). We found that lower temperature produces an amorphous phase, whereas higher temperature induces a large aggregate. We obtained the monodispersed MnCoO nanocubes at approximately 90°C, exhibiting the best ORR performance with an electron‐transfer number of 3.86. We developed a topotatic growth method involving an Co(OH)2nanosheet that allowed a water‐based reaction for the formation of the MnxCo3−xO4(x = 0.005) spinel nanocubes with Mn(II)/Co(II) salts. The nanocubes prepared at a reaction temperature of 90°C exhibit the best ORR activity due to the crystalline phase, smaller size, better particle distribution, and higher Mn incorporation than other reaction temperatures (70, 120, 150, and 180°C).