To improve the quality of modified atmosphere (60% CO/15% O/25% N)-packaged or vacuum-packaged bigeye tuna () chunks, an edible film containing whey protein isolates (WPI) were added. During storage at 2 °C, the samples coated with WPI prior to packaging exhibited slower microbial growth, thiobarbituric acid (TBA), and total volatile basic-nitrogen (TVB-N) values than did those without films. On comparing the two formulations of WPI with 4 and 8% (v/v) glycerol, it was observed that WPI containing 8% glycerol induced more severe weight loss but retarded the lipid oxidation more effectively. The usage of WPI films with 8% glycerol is proved to be helpful to enhance the effect of modified atmosphere packaging on the quality of tuna, as the samples (MAP-2) displayed the lowest bacterial counts (3.63 log CFU/g) and TBA (0.349 mg malondialdehyde (MDA)/kg) and TVB-N (12.94 mg N/100 g) contents.