Objectives: To determine the proportion of care provided to children with acute gastroenteritis (AGE) in Australia consistent with clinical practice guidelines. Methods: Indicators were developed from national and international clinical practice guideline (CPG) recommendations and validated by an expert panel. Medical records from children ≤15 years presenting with AGE in three healthcare settings–Emergency Department (ED), hospital admissions and General Practitioner (GP) consultations–from randomly selected health districts across three Australian States were reviewed. Records were audited against 35 indicators by trained paediatric nurses, to determine adherence to CPGs during diagnosis, treatment, and ongoing management. Results: A total of 14,434 indicator assessments were performed from 854 healthcare visits for AGE by 669 children, across 75 GPs, 34 EDs and 26 hospital inpatient services. Documented adherence to guidelines across all healthcare settings was 45.5% for indicators relating to diagnosis (95% CI: 40.7–50.4), 96.1% for treatment (95% CI: 94.8–97.1) and 57.6% for ongoing management (95% CI: 51.3–63.7). Adherence varied by healthcare setting, with adherence in GPs (54.6%; 95% CI: 51.1–58.1) lower than for either ED settings (84.7%; 95% CI: 82.4–86.9) or for inpatients (84.3%; 95% CI: 80.0–87.9); p<0.0001 for both differences. The difference between settings was driven by differences in the diagnosis and ongoing management phases of care. Conclusions: Adherence to clinical guidelines for children presenting to healthcare providers with AGE varies according to phase of care and healthcare setting. Although appropriate diagnostic assessment and ongoing management phase procedures are not well documented in medical records (particularly in the GP setting), in the treatment phase children are treated in accordance with guidelines over 90% of the time.