This study was conducted to improve achievement motivation through cognitive behavior therapy group counseling for class VIII students at SMP Negeri 15 Mataram. This study used a Classroom Action Research (CAR) design with two cycles. The sample of this study was the population in class VIII-1 m as many as 32 students. The data collection technique used was an achievement motivation questionnaire. The researcher used a data analysis technique with a percentage technique. The results of the study showed that cognitive behavior therapy (CBT) group counseling was effective in improving students' achievement motivation. ABSTRAKPenelitian ini dilakukan untuk meningkatkan motivasi berprestasi melalui konseling kelompok cognitive behavior therapy pada siswa kelas VIII di SMP Negeri 15 Mataram. Penelitian ini menggunakan desain penelitian Tindakan Kelas (PTK) dengan dua siklus. Sampel penelitian ini adalah populasi di kelas VIII-1 msebanyak 32 orang siswa. Teknik pengumpulan data yang digunakan adalah angket motivasi berprestasi. Peneliti menggunakan teknik analisis data dengan teknik persentase. Hasil penelitian menunjukan konseling kelompok cognitive behavior therapy (CBT) efektif dapat meningkatkan motivasi berprestasi siswa.