Background: Antibiotics are frequently prescribed in residential aged care facilities (RACFs), with up to 70% of residents receiving systemic antibiotics annually (Mody et al., 2015; Nicolle et al., 2000). Older adults are particularly vulnerable to antibiotic-associated harms due to multimorbidity, polypharmacy, frailty, and age-related physiological changes (Gutiérrez-Valencia et al., 2018; Pazan & Wehling, 2021). However, evidence remains fragmented, with inconsistency in how harms are defined and measured. Aims: To map the types of antibiotic-associated harms reported among older adults in RACFs, and to examine how these harms are defined, operationalised, and measured. Methods: This scoping review follows Arksey and O’Malley (2005), refined by Levac et al. (2010) and Peters et al. (2020), and is reported according to PRISMA-ScR (Tricco et al., 2018). A systematic search of Medline (n=238), CINAHL (n=155), EmCare (n=256), Scopus (n=181), and Web of Science (n=3), supplemented by handsearching (n=1), identified 834 records. Following duplicate removal, records were screened for eligibility, with full-text review and data extraction underway. Preliminary Findings: Early screening indicates substantial heterogeneity in reported harms and outcome measures. Frequently identified harms include antibiotic-associated diarrhoea, Clostridioides difficile infection, adverse drug reactions, and antimicrobial resistance outcomes, with inconsistent definitions and measurement approaches across studies. Conclusions/Implications: This review will provide a comprehensive evidence map of antibiotic-associated harms in RACF populations, informing future research and antimicrobial stewardship initiatives in aged care.