There exist many studies on modeling competencies and their promotion; however, there is a need to investigate what modeling competencies are and how they vary in lower and higher-achieving groups of students in mathematics within the current modeling literature domain. This study examined how mathematical modeling competencies were displayed in seventh-grade students working in two groups. It was qualitative and took competencies from existing literature into a detailed analysis of the modeling situation. The findings firmly supported the premise that higher-achieving groups exhibit higher levels of modeling competencies than lower-achieving groups. The differences in the levels of groups were more apparent in competencies of a sense of direction, planning and monitoring, understanding, mathematizing, and validating. Recommendations for further studies include studies of heterogeneous groups and further teacher development in modeling.