Tehran University of Medical Sciences Nursing Practice Today 2383-1154 0 0 2026 06 09 4524 4524 EN Ivo da Costa Polytechnic Institute of Bragança School of Health Sciences, Bragança, Portugal AND Emergency Department, Tâmega and Sousa Local Health Unit, Penafiel, Portugal Marlene Ribeiro Emergency Department, Tâmega and Sousa Local Health Unit, Penafiel, Portugal AND Abel Salazar Institute of Biomedical Sciences, University of Porto, Porto, Portugal AND RISE-Health, Faculty of Medicine, University of Porto, Porto, Portugal Luísa Castro Department of Population Studies, RISE-Health, School of Medicine and Biomedical Sciences, University of Porto, Porto, Portugal Andreia Teixeira RISE-Health, Faculty of Medicine, University of Porto, Porto, Portugal Matilde Martins Polytechnic Institute of Bragança School of Health Sciences, Bragança, Portugal AND Centro de Pesquisa para Vida Ativa e Bem-Estar, Instituto Politécnico de Bragança, Campus de Santa Apolónia, Bragança, Portugal 2025 09 29 2026 04 13 Background & Aim: Advanced Practice Nursing plays a crucial role in improving healthcare access, quality, and efficiency, being increasingly recognized in Portugal as a growing professional field. However, no validated instrument exists in Portugal to rigorously assess advanced practice nursing competencies. The Advanced Practice Nursing Competency Assessment Instrument, originally developed and validated in Spain, represents a robust tool for this purpose. This study aimed to cross-culturally adapt and validate the Advanced Practice Nursing Competency Assessment Instrument for the Portuguese context. Methods & Materials: This methodological study was conducted in two phases. Cross-cultural adaptation followed established stages: two independent forward translations, synthesis, two back-translations, expert committee review, pre-test, and feedback to the original author. Psychometric evaluation used a cross-sectional sample of nurses from a local health unit in Northern Portugal. Analyses included descriptive statistics, exploratory factor analysis through principal component analysis, and internal consistency calculated by Cronbach’s alpha, item–total, and inter-item correlations. Results: Expert consensus was achieved during the review process. The pre-test with a sample size of thirty-five nurses confirmed instrument clarity and usability. The validation sample included two hundred and sixty-four nurses and specialist nurses. Seven factors explained sixty-six percent of the total variance, representing a reduction from the original eight-factor structure. Two dimensions, Quality Management and Care Management, converged into a single factor in the Portuguese version. The scale demonstrated excellent reliability, with a total Cronbach’s alpha of 0.960, factor alphas ranging from 0.821 to 0.916, and adequate corrected item–total correlations. Conclusion: The Portuguese version demonstrates adequate content validity, a coherent factor structure, and excellent reliability, supporting its use to assess advanced practice nursing competencies in the Portuguese health system. https://npt.tums.ac.ir/index.php/npt/article/view/4524