GaFeO3-type oxide films are promising multiferroic materials due to their coexistence of ferroelectricity and ferrimagnetism at room temperature. For device applications, understanding the thickness dependence of their ferroelectric properties is crucial. In this study, we investigated the ferroelectric behavior of GaFeO3-type oxide films as a function of thickness. Notably, the GaFeO3-type structure is not perovskite but consists of three octahedral and one tetrahedral cation sites. Clear ferro