Most questionnaires used for managerial purposes have been developed in Anglo-Saxon countries and then adapted for other cultures. However, this process is controversial. This paper fills the gap for more culturally sensitive assessment instruments in the specific field of human resources while also addressing the methodological issues that scientists and practitioners face in the development of questionnaires. First, we present the development process of a Personal and Motive-based competencies questionnaire targeted to Spanish-speaking countries. Second, we address the validation process by guiding the reader through testing the questionnaire construct validity. We performed two studies: a first study with 274 experts and practitioners of competency development and a definitive study with 482 members of the general public. Our results support a model of nineteen competencies grouped into four higher-order factors. To assure valid construct comparisons we have tested the factorial invariance of gender and work experience. Subsequent analysis have found that women self-rate themselves significantly higher than men on only two of the nineteen competencies, empathy (p < .001) and service orientation (p < .05). The effect of work experience was significant in twelve competencies (p < .001), in which less experienced workers self-rate higher than experienced workers. Finally, we derive theoretical and practical implications.