AbstractBackground and ObjectivesOat milk is a plant‐based milk alternative and rich in various nutrients, however, the liquid product with a shorter shelf life limits its sales and consumption. This study is designed to develop an oat milk powder (OMP) using spray drying and improve the stability of reconstituted OMP by adding stabilizers.FindingsResults revealed that the optimal spray drying temperature was 160°C and the feed rate was 14 mL/min. The developed OMP showed higher bulk density compared to commercial soymilk powder. Furthermore, OMP maintained high contents of nutrients, including total phenol, β‐glucan, and various essential amino acids. The addition of stabilizers in OMP significantly decreased the turbidity and increased the pH stability, thermal stability, and freeze‐thaw stability of reconstituted OMP.ConclusionThe developed OMP product has abundant nutrients as well as stable physiochemical properties. Xanthan gum is the most effective stabilizer in improving the stability of reconstituted OMP across a wide range of pH and temperature.Significance and NoveltyThis study was the first to process oat milk into powder products and compare the effectiveness of different stabilizers in improving its stability. Our results suggest that OMP is a promising plant‐based beverage with stable physiochemical properties.