The aim of the present study was to investigate the physicochemical and sensory properties of yogurt fortified with chia seed mucilage and oil, as a rich source of omega-3 fatty acids. For this purpose, mucilage (0.213%), free and encapsulated oil (3.41%) were added to the yogurt formulation. The prepared sampleswere compared in terms of some physicochemical (pH, titratable acidity, syneresis, dry matter, peroxide values and color attributes) and sensory properties with control (without oil and mucilage) during storage for 30 days at refrigerator temperature (4 °C).The results showed that the addition of mucilage and chia seed oil in a free and encapsulated forms caused a significant increase in water holding capacity (decrease in syneresis), acidity (decrease in pH) and dry matter during storage (p <0.05). In addition, the sample containing mucilage and encapsulated oil showed the lowest color difference (∆E) with the control. Furthermore, this sample showed an increase in whiteness index (WI) and a decrease in yellowness index (YI) compared to the sample containing free oil. The amount of peroxide value in the samples containing free and encapsulated oil after 30 days of storage was 3.19 and 1.16 meq / kg of oil, respectively, which indicates the protective effect of encapsulation process against oxidation of samples. Evaluation of sensory attributes showed that the addition of mucilage and encapsulated chia seed oil did not have significantly effects on the sensory properties of fortified yogurt samples (p˃0.05).