Expert judgement has been established as a highly recommended method to ensure the validity and reliability of a research instrument. In the specific context of this study, its main function is to ensure that the questions asked in the questionnaire meet fundamental criteria, such as precision, clarity, representativeness, relevance, simplicity, and comprehensibility. In addition, expert judgment also focuses on evaluating the structure, format, and proper presentation of the questionnaire, with the aim of optimizing its usability and effectiveness. Methodology: To carry out the expert judgement in this study, a diverse group of highly qualified participants in different relevant disciplines has been selected. This group includes a philologist specializing in language, a statistical professional with experience in measuring instrument design, as well as three dentists specializing in pediatric dentistry. Each participant will be provided with a copy of the previously prepared questionnaire and asked to provide their assessments and contributions based on their experience and expertise. Results: After carrying out the evaluation in a focus group and expert judgement, it has been possible to obtain an instrument that meets high quality standards. There is a remarkable internal coherence between the questions asked, as well as a sufficiency in the coverage of the key aspects related to the subject of study. In addition, a high level of relevance and clarity in the questions has been achieved, which contributes to their understanding and proper interpretation by the participants. Conclusion: it has been determined that the instrument analyzed is valid to evaluate knowledge, attitudes, and practices from dentistry to identify possible child abuse.