The recently developed water‐insoluble tegoprazan (TPZ) belongs to the biopharmaceutical classification system (BCS) class II group was formulated through solid dispersion (SD) technology. SD formulations of TPZ were prepared using hydroxymethylcellulose (HPMC) and polyvinylpyrrolidone (PVP) polymers via the solvent evaporation method. SDs were characterized by scanning electron microscopy (SEM), powder x‐ray diffraction (PXRD), and differential scanning calorimetry (DSC). In addition, the equilibrium solubility of SDs, in vitro dissolution, and in vivo bioavailability (BA) study in rats were performed. PXRD and DSC revealed that TPZ was successfully transformed to amorphous forms in SDs. The equilibrium solubility was enhanced by 15–18‐fold, and in vitro dissolution was improved by approximately 2.2‐fold. Consequently, the BA of TPZ was increased up to 2.1‐fold. In conclusion, the use of SDs of TPZ using HPMC and PVP are considered a potential strategy to improve the therapeutic effect of TPZ via enhanced dissolution and BA.