Soft skills represent psychological attributes that inform how people learn, think, and act. Measuring soft skills is important because they are variables that allow students to predict their professional future and career orientation. There is often a lack of instruments for evaluating soft skills in educational settings. In this study, we present the development of the SKILLS and Attitudes in the ONE Questionnaire (SKILLS-in-ONE). This test examines the most frequent soft skills in the educational sector in a practical manner. A total of 1496 students responded to the SKILLS-in-ONE. Exploratory factor analysis and structural equation modeling were used for different samples of students. The reliability was calculated using several internal consistency indices. Strong statistical evidence supporting the construct validity of the test was obtained. Reliability was acceptable for all scales. In conclusion, the SKILLS-in-ONE, consisting of 74 items, provides a valid and reliable measure of the 13 most common soft skills in the educational context, and measures three personal styles of a new hypothetical theoretical model.