Mathematics plays a crucial role in facilitating students to develop various skills in the 21 st century. It is important for teachers to adapt instructional models and tools based on the characteristics of the current generation. The objective of this research is to describe the process and outcomes of developing project-based learning materials on 7th-grade statistics that are valid, practical, and effective. This study utilized the Plomp development model, which consisted of preliminary research, prototyping phase, and assessment phase. The research subjects were divided into two schemes: the micro-evaluation test involves two teachers, each teaching six students in 7th-grade, while the try-out test involved one teacher teaching 32 students in 7th-grade at one of junior high schools in Surabaya. The research instruments used include validation sheets, questionnaires, implementation feasibility sheets, and learning outcome assessments. Data analysis techniques were employed to determine the criteria of validity, practicality, and effectiveness. Based on the conducted research, the project achieved high validity criteria, with 91.8%, 91.1%, and 97.78% for the instructional module and 95.2%, 93.6%, and 96% for the project worksheets through validation test. The project-based learning materials also met expected practicality criteria by walkthrough test and actual practicality, with 86.36% for micro-class 1 and 85.79% for micro-class 2. Furthermore, the effectiveness criteria were met as the try-out class achieved a classical mastery level of 87.5%.