The objective of this study was to determine the combined effects of bovine casein or caprine casein and resveratrol on the chemical stability of α-tocopherol in sunflower oil-in-water emulsions. The highly hydrophobic nature of types I and II caprine caseins may improve the stability of resveratrol in dairy food systems. Previous studies have reported an increase in the chemical stability of α-tocopherol in the oil phase of sunflower oil-in-water emulsions stabilized by whey proteins when the cis-isomer of resveratrol partitioned into the oil-in-water interface. The whey proteins were also useful to entrap resveratrol, which is a hydrophobic bioactive compound. Sunflower oil-in-water emulsions (5% wt/wt) stabilized with bovine casein or caprine caseins type I and type II (0.5% wt/wt), α-tocopherol (0.015% wt/wt), and resveratrol (0.024% wt/wt) were prepared using a high-pressure homogenizer. The pH of the emulsions were adjusted to 7.0. The chemical stability of α-tocopherol was assessed by measuring the changes in its concentration in the emulsions during incubation at 21°C for 28 d using a HPLC method. The chemical stability of α-tocopherol increased significantly (P < 0.05) in emulsions with types I and II caprine caseins compared with bovine casein. Microencapsulation of α-tocopherol with either caprine casein-resveratrol or bovine casein-resveratrol protected α-tocopherol in sunflower oil-in-water emulsions and significantly reduced (P < 0.05) the chemical degradation of α-tocopherol during 28 d of storage at 21°C compared with the treatments without resveratrol. This information will be useful for understanding the behavior of α-tocopherol in dairy foods.