Objective: Sepsis-induced acute kidney injury (AKI) is considered as a life-threatening complication of sepsis. The purpose of this study is to clarify the involvement of annexin A3 (ANXA3) in sepsis-related AKI. Material and Methods: Lipopolysaccharide (LPS) was used to establish a cell model based on HK2 cells. ANXA3 expression was quantified through quantitative real-time polymerase chain reaction. Cell proliferative capacities were assessed through 5-ethynyl-2 '-deoxyuridine proliferation, cell counting kit-8, and colony formation experiments. Flow cytometry was utilized to analyze apoptotic cells. Inflammatory and oxidative stress indicators were measured by employing corresponding commercial assay kits. Endoplasmic reticulum (ER) stress markers were quantified through western blot analysis. Results: ANXA3 levels were significantly elevated in HK2 cells treated with LPS and in serum samples obtained from patients with AKI and sepsis (P < 0.001). LPS treatment exacerbated cellular damage, leading to increased ER and oxidative stresses, apoptosis, and inflammation, whereas knocking down ANXA3 significantly reversed these changes (P < 0.001). Conclusion: Interference with ANXA3 protected HK2 cells from LPS-induced cell injury through inhibiting inflammation, oxidative stress, apoptosis, and ER stress.