Objective: The objective of this study was to formulate, evaluate, and optimize a floating in situ gel of pantoprazole sodium. Materials and Methods: In situ gel formulations were prepared using varying concentrations of sodium alginate, calcium carbonate, sodium citrate, and xanthan gum. The mechanism involved was pH-triggered ionic gelation. All formulations were subjected to various evaluation parameters. Results: Formulation F8, containing 0.04 g of pantoprazole sodium, 2 g of sodium alginate, 1 g of CaCO3, 1 g of xanthan gum, and 0.25 g of sodium citrate, was selected as the optimized batch. It had a floating time of 44.33 seconds and a drug content of 97.0%. FTIR studies revealed no incompatibility. The optimized batch passed accelerated stability studies with no significant change in drug content. An in-vivo study on albino Wistar rats demonstrated significant anti-ulcer effects of the optimized pantoprazole sodium formulation. Conclusion: The study concluded that the hydrodynamically balanced oral in situ gel of pantoprazole sodium could be an effective dosage form, remaining buoyant and sustaining drug release for 8 hours.