Perovskite oxides have gained significant attention as bifunctional electrocatalysts for water splitting due to their tunable electronic structures and robust stability. Our work focuses on designing transition metal-based perovskite oxide catalysts, which directly addresses the limitations of traditional noble-metal catalysts by offering improved activity, stability, and affordability. In this work, we synthesized SrCoO₃ (SCO) perovskite oxides via a sol–gel method followed by thermal treatment at various calcination temperatures (800 °C, 900 °C, and 1000 °C) to investigate their bifunctional electrocatalytic activity toward the hydrogen and oxygen evolution reactions (HER and OER). X-ray diffraction analysis confirmed the formation of a well-crystallized rhombohedral perovskite phase (space group R32:H), with impurity phases of Co₃O₄ and SrCO₃ observed at lower temperatures and diminishing at higher calcination temperatures. FESEM imaging revealed a progressive morphological evolution, where increasing the calcination temperature enhanced grain growth, surface smoothness, and particle densification. Electrochemical measurements demonstrated that the sample calcined at 1000 °C (SCO1000) exhibited superior HER activity with a low overpotential of 473 mV at 10 mA cm^-2 and a Tafel slope of 112.62 mV dec^-1, outperforming SCO900 and SCO800. Conversely, for OER, the SCO800 sample showed the best performance, delivering an overpotential of 420 mV at 10 mA cm^-2 and the lowest Tafel slope of 90.59 mV dec^-1. These results indicate that thermal treatment not only influences the crystallinity and phase purity but also critically modulates the surface structure and electrochemical behavior of SCO, enabling selective optimization for HER or OER through calcination temperature control.