The aim of this study was to evaluate films from Whitemouth croaker protein isolate (CPI) with or without addition of montmorillonite (MMT). Results showed that incorporation of organophylic clay montmorillonite decreased the solubility, transparency and water vapor permeability (WVP) (3.82 g mm/m-2 day-1 KPa-1) when compared with pure CPI film (8.57 g mm/m-2 day-1 KPa-1). Films with montmorillonite showed increased mechanical properties, tensile strength and elongation percentage at break point (11.4 MPa and 10.9%, respectively), than the pure CPI film (9.8 MPa and 9.3%). The films produced from CPI with MMT showed better properties of WVP, tensile strength, scanning electron microscopy (SEM), structural analysis in Fourier Transform Infrared (FT-IR) spectroscopy and X-ray diffraction (XRD).