To investigate the effects of mixed starter cultures on the quality of macadamia nut yogurt during refrigerated storage, combinations of Streptococcus thermophilus (St) and Lactobacillus delbrueckii subsp. bulgaricus (Ld) with L. casei (Lc), L. acidophilus (La), L. plantarum (Lp), or L. rhamnosus (Lr) were evaluated. Changes in physicochemical properties, viable cell counts, antioxidant capacity, and sensory characteristics were monitored during 21 days of storage at 4 ℃.The results showed that the Ld/St/La group exhibited significantly higher titratable acidity and lower pH values during the middle and late stages of storage than the control group (Ld/St), indicating stronger post-acidification ability. The Ld/St/Lc and Ld/St/Lp groups also showed relatively strong acidification performance. Shear viscosity remained generally stable in most groups throughout storage, whereas a significant decrease was observed in the Ld/St/Lp group on day 21. In terms of microbial viability, the Ld/St/La group maintained the highest lactobacilli counts, while relatively high streptococci counts were observed in the Ld/St, Ld/St/Lc, and Ld/St/La groups. By contrast, the addition of Lp or Lr did not significantly improve bacterial survival during storage. Among all treatments, the Ld/St/La group exhibited the highest total phenolic content, total flavonoid content, DPPH radical scavenging activity, hydroxyl radical scavenging activity, and ferric reducing antioxidant power, suggesting a superior capacity to preserve or promote antioxidant-related properties during refrigerated storage. Although the addition of Lc, Lp, or Lr also improved antioxidant capacity at the middle and late storage stages, their effects were less pronounced than those of La. Sensory evaluation indicated that the Ld/St/Lc and Ld/St/Lr groups achieved better overall acceptability. Overall, the Ld/St/La combination was more effective in improving acidification performance, maintaining lactobacilli viability, and enhancing antioxidant capacity, whereas Ld/St/Lc and Ld/St/Lr showed advantages in sensory quality. These findings provide useful evidence for selecting mixed starter cultures and optimizing the production of macadamia nut yogurt.