This research, conducted in grade VII of UPT SMPN 41 Medan, aims to describe the effect of Connected Mathematics Project (CMP) learning on students' mathematical connection abilities in the topic of triangles and quadrilaterals. The research method used a quantitative approach with a quasi-experimental research method. The population in this study was all grade VII students of UPT SMPN 41 Medan. The sampling technique used random sampling, selecting grade VII-2 students as the experimental class and grade VII-4 students as the control class. The Pretest and Posttest results were analyzed using normality and homogeneity tests. Based on the normality and homogeneity tests, the results showed that the sample was normally distributed and homogeneous. Furthermore, a hypothesis test was conducted. The results of the independent samples test showed a significant difference in students' mathematical connection skills between the control and experimental classes. The SPSS analysis showed a significance value of p = 0.000, indicating that p <0.05, indicating an effect of the Connected Mathematics Project (CMP) learning on students' mathematical connection skills. This was also evident from the results of the comparative hypothesis test of two samples, with an average post-test score of 74.55 for the experimental class and an average score of 46.28 for the control class, with a T-value of 13.87. This T-value was higher than the T-table value of 2.001. Therefore, the hypothesis Ho was rejected and Ha was accepted. Therefore, it can be concluded that the Connected Mathematics Project (CMP) learning had a significant effect on students' mathematical connection skills.