Abstract- This study aims to determine how much the relationship between the effectiveness of the implementation of remedial learning and the group investigation approach to learning completeness in Economics subjects. The implementation of remedial learning is assistance provided to students who have not achieved mastery learning. Remedial learning with group investigation approaches so students are more active and free to express opinions. Learning completeness is the minimum level of achievement of student learning. Students can be said to be complete or mastery if the learning outcomes reach 75% of the assessment. This research used a descriptive method with a quantitative approach. The sample of this study is a saturated sample of 30 people by taking samples to class XI students from SMA 8 Banjarmasin. Methods and techniques of data collection using observation and observation sheets and achievement tests. The results of the inter-observer agreement test analysis are indicated by the coefficient Kappa with an average of between 0.64 to 0.81. The validity test of achievement tests are indicated by the coefficient between 0.38 to 0.67 and the reliability of achievement tests is 0.63. Chi Squared Test results show 27,107 (p < 0.01), so it can be said that there is a significant relationship of the effectiveness of the implementation of remedial learning with a group investigation approach to learning completeness in economic subjects.