Purpose: The purpose of this study was to ascertain antibiotic-associated acute kidney injury (AKI) in older adults aged 65 years or above in New Zealand using a case-crossover study design. Methods: We used the International Statistical Classification of Diseases and Related Health Problems, Tenth Revision, Australian Modification code N17.9 to identify all individuals aged 65 years and above with a diagnosis of incident AKI between January 01, 2005, and December 31, 2020, from the New Zealand National Minimum Data Set. We created a case-crossover cohort for antibiotic exposures, with a 3-day observation period and two 30 days washout periods, summed up to a 66-day study period. We calculated the changed odds of AKI due to exposures to an antibiotic as matched odds ratios and their 95% confidence intervals, using conditional logistic regression. Results: We identified a total of 2399 incident cases of AKI between 2005 and 2020 among older adults. The adjusted odds of consuming a sulphonamide antibiotic during the case period was 3.57 times (95% CI: 2.86 to 4.46) higher than the reference period among the incident AKI cases. Fluoroquinolone utilisation was also associated with incident AKI (adjusted OR = 2.56; 95% CI: 1.90 to 3.46). The number needed to harm for sulphonamides and fluroquinolones were 6.55 (95% CI: 5.15 to 8.65) and 21.38 (95% CI: 13.97 to 36.41), respectively. Conclusion: The potential of sulphonamides and fluoroquinolones to be associated with AKI raises the significant need for vigilant prescribing of these antibiotics in frail older adults.