Load frequency control (LFC) in interconnected power systems is critical, as it can lead to frequency instability and compromise overall system stability. By effectively controlling tie-line power between interconnected areas, this challenge can be addressed. This paper presents the design and implementation of a second-order sliding mode control (SOSMC) approach for LFC in an interconnected two-area power system, demonstrating its performance in mitigating frequency deviations and achieving minimal steady-state error. Simulation results confirm that the proposed SOSMC outperforms conventional sliding mode controllers (SMC) and PID controllers with respect to enhanced damping characteristics, reduced chattering, and improved robustness across various loading conditions. These findings position SOSMC as a highly effective and reliable control strategy for maintaining tie-line power balance and ensuring frequency stability in interconnected power systems.