The objective of this study was to evaluate the structuring capacity of anhydrous milk fat (AMF) in lipid bases from blends made with AMF and high oleic sunflower oil (HOSO) in proportions of 100:00; 90:10: 80:20; 70:30; 60:40; 50:50 (w/w). The lipid bases were characterized by thermal behavior of crystallization and melting (-80 to 80 °C), crystallization kinetics (15 °C), microstructure (15 and 30 °C), and polymorphism after 7 and 50 days of stabilization at 15 °C. The addition of HOSO to the AMF resulted in two defined crystallization and melting peaks, and the amount of energy released for thermal transition was proportional to the number of molecules involved in the events. The Avrami crystallization constant (k) was significantly reduced with increasing the HOSO concentration, with Avrami exponents (n) between 1 and 2 for milk fat (AMF:HOSO 100:00), suggesting growth of needle-shaped crystals from instantaneous or sporadic nuclei. Avrami exponents (n) between 3 and 4 were observed in the blends with the addition of HOSO to AMF, indicating the growth of spherulitic crystals with instantaneous nucleation, or disc type crystals with sporadic nucleation. Similar crystals were observed in the microstructures at 30 °C. The blends exhibited crystals with diameters varying between 5.31 and 5.83 μm and polymorphic habit in β', which is characteristic of AMF, after 50 days of stabilization at 15 °C. Based on the crystallization behavior and the microstructure of the crystalline network, it can be concluded that the AMF governed the crystallization of the lipid bases, giving structure and plasticity to the system for different technological applications, such as ice-cream mixes, spreads, and fillings.