Purpose: To evaluate how physiotherapists across three countries (Australia, New Zealand (NZ) and Ireland) diagnose greater trochanteric pain syndrome (GTPS) using clinical tests and imaging findings, and how physiotherapists update their knowledge regarding GTPS. Design: Cross-sectional observational study of physiotherapists. Methods: An online survey was distributed to registered physiotherapists in Australia, NZ and Ireland. Ordinal and nominal data were analysed using frequency counts or mean ranks; medians and interquartile ranges were calculated for numerical data. Comparisons between the three countries were made using Chi-squared analyses for nominal/ordinal data and Kruskal Wallis tests for numerical data. Statistical significance was set at p < 0.05. Results/findings: Valid responses were received from 361 physiotherapists; 61% were female and 79.8% worked in private practice. Most respondents were very confident in diagnosing GTPS (67.9%) and incorporated a range of symptoms and tests, including validated tests, in their diagnosis. However, many physiotherapists were not commonly using some available validated diagnostic tests (e.g. FABER and FADER-R). Approximately 30% of physiotherapists used imaging to inform assessment, with ultrasound being most preferred. Physiotherapists rated hands-on experience as most valuable for updating their knowledge of GTPS, followed by courses. Conclusion: While most clinicians appear to be using current evidence in their assessment of patients with GTPS, a proportion use suboptimal methods and/or a limited range of diagnostic tests, suggesting that despite their confidence in diagnosis, further knowledge translation may be required. Future research should determine the best methods of facilitating knowledge acquisition and translation of research into practice.