Background Antiepileptic drugs (AEDs) are widely used in residential aged care (RAC), yet temporal prescribing trends in overall and specific AED use remain unclear. This study examined the prevalence and trends of AED use, including differences by drug generation and resident characteristics, in RAC. Methods We conducted a retrospective cohort study using routinely collected data from 23 Sydney-based RAC homes managed by one provider (July 2014–December 2025), including 11,816 residents aged ≥65 years. AEDs were identified using Anatomical Therapeutic Chemical classification. Adjusted prevalences and risk factors were estimated using mix-effects logistic regression models, accounting for demographics, comorbidities, year, and home. Results Adjusted prevalence of AED use increased from 15.2% in 2014 to 22.7% in 2019, then stabilised at ~20%. Use of first-generation AEDs declined (8.7% to 6.9%), while second-generation AEDs increased (8.1% to ~14.9%) and became dominant; third-generation AEDs remained rare. Among individual agents, gabapentin showed the largest increase (6.3% to ~11.9%), and levetiracetam rose steadily, whereas valproate remained stable and clonazepam declined. AED use decreased with age and was similar by sex, and was lower among residents with dementia. Although prevalence was higher among those with epilepsy/seizure (~68%), a substantial proportion of those without epilepsy/seizure (~16.7%) also received AEDs. In mixed-effects models, epilepsy/seizure, bipolar disorder, and pain were key predictors, while dementia was associated with lower odds. Significant variation was observed across homes. Conclusions There are evolving prescribing patterns and potential off-label use of AEDs in RAC, underscoring the need for ongoing monitoring and optimisation of medication use.