In a world where physical activity and social participation are fundamental pillars for a full, healthy, and quality life, confidence in walking emerges as a fundamental aspect to be assessed, especially in older adults. The purpose of this study was therefore to develop a Portuguese (Euro-pean) version, linguistically and psychometrically adapted, of the Ambulatory Self-Confidence Questionnaire (ASCQ); A translation method was used followed by an assessment of its validity and reliability. The Portuguese version was completed by 173 older adults. To assess reliability was used Cronbach’s Alpha and Intraclass Correlation Coefficients (ICC). For sociodemographic and clinical characterization, as well as for the questionnaire scoring was used descriptive statistical analysis. Pearson's correlation (r), Student´s t-test and ANOVA were used to analyse the criterion and con-struction validity; The Portuguese interactions of ASCQ was effectively translated and adjusted, revealing exceptional internal consistency and test-retest reliability, as reflected in Cronbach's alpha and ICC values of 0.95. No Floor Effect was observed, however, a Celling Effect was identified (3.5%). Criterion and construct validity were verified because all the correlations established were statistically significant; The adaptation of the ASCQ to Portuguese culture is adequate, making it valid for use within the Portuguese population of Portugal.