This study aims to describe the process and results of the development of contextual learning tools to improve problem-solving skills, to describe the effectiveness of contextual learning on the material of simultaneous linear equations for grade VIII students.This research was a development research. Learning tools developed in this research were lesson plan, worksheets, and problem-solving test. Learning device development model used was a 4-D development model consisting of four phases namely, defining, designing, developing and disseminating. From the result of analysis conducted by the researcher, it was obtained that: 1) contextual learning device has fulfilled the criteria of good learning devices because it was stated as valid, practical and effective, 2) contextual based learning was effective to teach the material of simultaneous linear equations, and 3) students' mathematical problem-solving skill that follow contextual learning increased.