Introduction <p>The aim of this study is to reach consensus and prioritise the most clinically important assessments, diagnostic classifications, and outcome measures by an international panel of experts for Legg-Calve-Perthes disease.</p> Materials and methods <p>A three-round modified e-Delphi survey was conducted between April and May 2025. Participants rated the clinical importance of 14 clinical assessments, 26 radiological assessments, eight diagnostic classifications, and 26 outcome measures identified by a scoping review. Consensus was defined as ≥ 75% agreement. In the final round, items in each category were prioritised for overall condition and by specific age groups (&lt; 6 years, 6–8 years, &gt; 8 years).</p> Results <p>Thirty-eight health professionals, from nine countries participated in round 1. Thirty-four completed all three rounds, a retention rate of 89.5%. Consensus and prioritisation for clinical use were achieved for 10 clinical assessments, three radiological assessments, three diagnostic classifications, and three outcome measures.</p> Conclusion <p>Paediatric specialists have reached consensus and prioritised methods to evaluate and diagnose Legg-Calve-Perthes disease in clinical practice. These results represent an important step towards improving continuity of care and the foundation for future development of clinical practice guidelines.</p>