The problem of this research aimed to reveal whether interpersonal communication could be improved through group guidance on assertive training techniques. This study aimed to investigate whether there is an increase in interpersonal communication through assertive training techniques group guidance services of the eighth grade students of Junior High School 1 Gisting in Academic Year of 2017/2018. The method used in this research was the quasi experimental method with one group pretest-posttest design. This research used the scale of interpersonal communication as the data collection techniques. For the data analysis technique, this research used Wilcoxon Matched Pairs Test. The results show the calculation that Zvalue= - 2.521 or less than Ztable = 1.645. Thus, Ho was rejected and Ha was accepted. The conclusion of this research reveals that group guidance service of assertive training technique could be used to improve interpersonal communication in the eighth grade students of Junior High School 1 Gisting in Academic Year of 2017/2018.Permasalahan penelitian adalah apakah komunikasi interpersonal dapat ditingkatkan melalui bimbingan kelompok teknik assertive training. Tujuan penelitian untuk mengetahui peningkatan komunikasi interpersonal melalui layanan bimbingan kelompok teknik assertive training pada siswa kelas VIII SMP Negeri 1 Gisting tahun ajaran 2017/2018. Metode penelitian ini adalah metode quasi eksperiment dengan one group pretes-posttest design. Teknik pengumpulan data menggunakan skala komunikasi interpersonal. Hasil analisis data menggunakan uji Wilcoxon Matched Pairs Test, diperoleh hasil Zhitung = - 2,521 hasilnya kurang dari Ztabel = 1,645 maka Ho ditolak dan Ha diterima. Kesimpulannya adalah penggunaan bimbingan kelompok teknik assertive training dapat meningkatkan komunikasi interpersonal siswa kelas VIII SMP Negeri 1 Gisting tahun ajaran 2017/2018.Kata kunci: assertive, bimbingan kelompok, komunikasi interpersonal