This work investigates the catalytic reactivity of mixed oxides containing B-site substituted CaMFeO3 (M = Cu, Mo and Co) perovskite synthesized via a modified EDTA-citric acid complexation method. The catalysts were tested for the heterogeneous Fenton-like reaction for the oxidative degradation of acid orange II (AOII) dye in the presence of H2O2. CaCuFeO3 exhibited the highest AOII degradation (97%) followed by CaMoFeO3 (90%), CaFeO3 (64%) and CaCoFeO3 (40%) within 60 min of reaction, and the reaction followed a pseudo-second-order kinetics model. Interestingly, the partial substitution of Cu in the B-site of CaFeO3 enhanced the reaction rate constant achieving a k value of 1.9 10-2 L mg-1 min-1, approximately twenty-one times higher than that of the blank catalyst CaFeO3. The enhanced catalytic reactivity of CaCuFeO3 is associated with the high reducibility of copper/iron ions within the B-site structure in the presence of oxidant which facilitated fast redox cycling of the active sites during catalysis.