The concomitant use of non-steroidal anti-inflammatory drugs (NSAIDs) and proton pump inhibitors (PPIs) potentially increases the risk of acute kidney injury (AKI). However, the risk of AKI has not been comprehensively assessed for the concomitant use of NSAIDs with gastroprotective agents such as misoprostol and PPIs. The objective of this study was to evaluate whether the use of various gastroprotective agents affects the risk of AKI in patients receiving NSAIDs. The data analyzed were obtained from the JMDC hospital-based administrative claims database between April 2014 and August 2022. Histamine-2 receptor antagonists (H2RAs) were compared with PPIs or misoprostol in patients receiving NSAIDs. The primary outcome was the incidence of AKI. The covariates considered were age and sex, admission to intensive care unit, presence of comorbidities based on the modified Charlson Comorbidity Index, and use of renin-angiotensin system inhibitors, loop diuretics, other diuretics, and lithium. AKI was identified by changes in serum creatinine. The distribution of AKI was analyzed using the log-rank test, and estimates of the incidence of AKI were compared among the groups using a Cox proportional hazards model with time-varying variables. Models were adjusted using a doubly robust method that accounts for the inverse probability of treatment weighting at baseline while adjusting for covariates. After screening, 11,688 patients were eligible for inclusion (1729 for H2RAs, 368 for misoprostol, and 9591 for PPIs). AKI occurred in 0.5% of H2RA recipients and 1.1% of PPI recipients; no AKI was observed in the misoprostol group. Compared with H2RAs, the risk of AKI tended to be higher with PPIs (adjusted hazard ratio 1.83, 95% confidence interval 0.92-3.63, p = 0.08). Compared with H2RAs, PPIs may increase the risk of AKI in patients receiving NSAIDs, although no statistically significant difference was observed. Further research is required to assess the risk trade-off with consideration of both peptic ulcer prevention and the increased risk of AKI in patients concurrently treated with NSAIDs and H2RAs, misoprostol, or PPIs.