In the last years, dairy industry researches have paid a great attention for the supplementation of various dairy products with natural additives to improve and enhance functional properties. In this study, the influence of using different levels of oat flour (1.0, 2.5, and 5.0%) on the quality of low fat probiotic labneh was investigated. The fat content of milk was standardized to 1%, and 3% of a commercial probiotic culture (ABT-5) was added to the experimental and control labneh. Labneh samples of all treatments were stored at 7±1°C for 20 days, and tested for chemical composition, rheological properties, microbiological quality, and sensory properties. The addition of oat flour had no significant effect on the chemical composition of labneh. On the other hand, addition of oat flour has improved the syneresis and viscosity and the organoleptic characteristics of low fat probiotic labneh. Overall, the low fat probiotic labneh containing 5% of oat flour was similar in the quality characteristics to the control sample made from milk containing 4% fat. The counts of S. thermophilus, L. acidophilus and B. bifidum were higher in all labneh treatments supplemented with oat flour than controls. S. thermophilus counts increased gradually in all treatments up to 10 days of storage, and then decreased while L. acidophilus and B. bifidum counts decreased gradually in all treatments up to the end of storage period but the counts were more than the minimum recommended counts to get the probiotic effect. According to the obtained results, it is recommended to use oat flour at a concentration of 5% for improving the physicochemical, microbiological and organoleptic attributes of low fat probiotic labneh.