Excessive consumption of dietary sugar has been linked to metabolic and neurocognitive dysfunction, yet the behavioral consequences remain insufficiently characterized. Using the IntelliCage automated behavioral system, we investigated the long-term impact of a high-sugar diet (HSD) on learning, memory, cognitive flexibility, activity, and addiction-like behaviors in mice. Adult swiss albino mice were divided into control (standard chow) and HSD groups for 6 weeks. Behavioral tasks included place learning, reversal learning, activity monitoring, and sucrose preference. Mice on HSD exhibited deficits in acquisition and retention of memory tasks, impaired reversal learning indicative of reduced cognitive flexibility, altered locomotor activity, and enhanced sugar preference resembling addiction-like behavior. These findings suggest that chronic HSD consumption impairs cognitive performance in mice, with implications for understanding diet-related neurocognitive disorders in humans.