This study aims to develop a structured scaffolding-guided inquiry (SSGI) learning model that is oriented toward nurturing argumentation skills to solve complex problems. Test the effectiveness of the SSGI model in improving students' argumentation skills to solve complex problems. This research is development research that refers to Dick and Carey. Test the effectiveness of the SSGI learning model in a quasi-experimental pre-test and post-test group design. Argumentation skills to solve complex problems data were collected using an essay test. The research sample used Physics Education students in the 4th semester (N = 30). The significance of the difference in pre-test and post-test scores was analyzed using the t-test. The impact of the SSGI is analyzed using effect size. The result of this study indicates that the SSGI enhances students' argumentation skills to solve complex problems. The increase in students' argumentation skills to solve complex problems was 7% in the high category, 57% in the medium category, and 36% in the low category. The effect size coefficient of the SSGI is 0.78 in the medium category. The SSGI syntax that contributes the most to growing argumentation skills to solve complex problems is the reasoning syntax. Then the next sequence is syntax exploration, closure, and orientation.