The main aim of this study was to entrap a fat-soluble vitamin (D3) and Tannic acid (TA) in nanophytosomes (NPHYs) to improve their stability and controlled release. The effects of phosphatidyl choline: TA ratio (P1:T2, P1:T1, and P2:T1) and the presence of D3 on the transmission electron microscope (TEM), particle size distribution and span, zeta potential, turbidity, stability, pH, total phenolic content (TPC), encapsulation efficiency (EE), particle size, antioxidant activity and in vitro release of TA and D3 were studied. A fine dispersion with particle size less than 100 nm was achieved for all NPHYs. Based on TEM, all samples had a smooth, spherical surface and formed small vesicles. The zeta potential varied from -65.2 to -55.26 mV. The P1:T2-D sample had the highest polyphenol content and antioxidant activities. Based on the thermal stability results, all samples were stable up to 50 °C. The P2:T1-D sample had the highest EE values for both D3 and TA (93.70 and 92.22%, respectively) and the lowest release rate in gastric conditions. The presence of D3 did not affect the stability of NPHYs. Therefore, the incorporation of TA and D3 in NPHYs can be considered a promising strategy in the food and pharmaceutical industries due to the improved physical and biological stabilities.