The purpose of this study was to investigate students’ outcome in knowledge aspect and attitude towards STEM (Science, Technology, Engineering and Mathematics) through validation, test and questionnaire. The design of this study used one group pretest-posttest design. Data collected from junior high school students (32.7% female and 67.3% male) who were analyzing based on descriptive quantitative and qualitative. The results indicated that, first, the instrument used in this study had contentedly validity and reliability. Second, the findings indicated that student knowledge significantly higher in the posttest as compared to the pretest. Last, the dimension of Science came in the first rank and followed by Technology-Engineering and going on Mathematics that showed the degree of attitudes towards STEM. The conclusion that learning STEM was effective to increase students’ outcome in  knowledge aspect that gain score confirmed has high categorized. The students respond towards STEM for career are very positive.