Peneliti mencoba menerapkan model project based learning terhadap pembelajaran senam aerobik. Tujuan penelitian yang ingin penulis teliti adalah untuk mengetahui bagaimana penerapan project based learning terhadap peningkatan kepercayaan diri siswa. Penelitian ini menggunakan metode Penelitian Tindakan Kelas. Penelitian dilaksanakan di SMP Negeri Satu Atap Jayakerta Kabupaten Karawang. Dengan objek penelitian kelas VIII-B yang berjumlah 26 orang. Proses penelitian dibagi menjadi dua siklus dan tiap siklus terdiri dari lima tindakan. Setiap tindakan menggunakan model project based learning untuk meningkatkan kepercayaan diri siswa. Data dikumpulkan menggunakan lembar observasi. Kemudian semua data yang terkumpul dianalisis menggunakan teknik presentase. Hasil analisis data menunjukan bahwa penerapan model project based learning dapat meningkatkan sikap kepercayaan diri siswa dalam mengikuti pembelajaran senam aerobik. Hal ini dibuktikan dengan peningkatan sikap percaya diri siswa tergolong pada kriteria sangat baik dengan presentase setiap tindakan adalah Siklus I tindakan 1 = 33%, tindakan 2 = 39%, tindakan 3 = 42%, tindakan 4 = 47%, dan tindakan 5 = 54%. Siklus II tindakan 1 = 61%, tindakan 2 = 71%, tindakan 3 = 78%, tindakan 4 = 86%, dan tindakan 5 = 91%. Dengan demikian dapat simpulkan bahwa penerapan model project based learning pada pembelajaran senam aerobik dapat meningkatkan kepercayaan diri siswa. ---------- Researcher tries to apply project based learning model to aerobic learning. The aim of this research is to find out how to apply project based learning model to improve student’s confidence. This study is using Classroom Action Research method. This research conducted in SMP Negeri Satu Atap Jayakerta Kabupaten Karawang. The objects of research class VIII-B are 26 student’s. The process of research is divided into two cycles and each cycle consists of five actions. Each action was using project based learning model to improve student’s confidence. Data collected by using observation sheet. All data gathered was analyzed by using percentage technique. The result shows project based learning model could improve student’s confidence in following aerobic learning activity. This is evidenced by the increase of student’s confidence belong to the very good criteria with the percentage of every actions are Cycle I action 1= 33%, action 2 = 39%, action 3 = 42%, action 4 = 47%, and action 5 = 54%. Cycle II action 1 = 61%, action 2 = 71%, action 3 = 78%, action 4 = 86%, and action 5 = 91%. Therefore, it can be concluded that the application of project based learning model in aerobic learning can improve students’s confidence
