Berdasarkan hasil refleksi mengajar di kelas VIII Sekolah X Manado, ditemukan kondisi kelas yang didalamnya terdapat para siswa yang menunjukkan respon yang pasif ketika mengikuti pembelajaran IPS Terpadu. Salah satu penyebab dari kondisi kelas tersebut ialah peneliti sebagai guru kebanyakan menggunakan metode ceramah ketika mengajar. Berdasarkan hal tersebut, peneliti memutuskan untuk melakukan suatu tindakan sebagai upaya untuk mengatasi permasalahan tersebut dengan menerapkan metode numbered heads together (NHT) dalam meningkatkan keaktifan belajar siswa kelas VIII pada pembelajaran IPS Terpadu. Metode penelitian yang digunakan dalam penelitian ini adalah penelitian tindakan kelas (PTK) model Kemmis dan Taggart yang dilaksanakan dalam dua siklus. Data penelitian diperoleh dari lembar observasi, angket siswa, lembar wawancara guru mentor, feedback mentor dan jurnal refleksi peneliti. Berdasarkan hasil perolehan data dari penelitian ini menunjukkan bahwa penerapan metode NHT dapat meningkatkan keaktifan belajar siswa, walaupun peningkatan tersebut belum mencapai kriteria ketuntasan minimal yang ditetapkan. Prinsip utama dari setiap tahapan pelaksanaan metode NHT yang meningkatkan keaktifan belajar siswa adalah heads together, yaitu para siswa dalam satu kelompok menyatukan pemikirannya untuk menjawab soal yang guru berikan dan dalam hal ini guru harus dapat mengontrol kelas dengan baik ketika para siswa mengikuti tahapan diskusi dari metode NHT. / Based on the reflection as the result of teaching grade VIII at X school in Manado, it was found that the condition of the class inside had students who showed that they had passive response when they followed Social Science subject. One of the reasons from that class condition was that the researcher used lecturing method when she taught the subject. Based on that problems, the researcher decided to do an action as an effort to solve that problems by implementing numbered heads together (NHT) in increasing the grade VIII students’ learning activeness of Social Science subject. The research method that was used in this research was Class Action Research (CAR) by Kemmis and Taggart model which was operated in two cycles. The research data was gotten from the observation sheet, students’ questionnaire, interview sheet of mentor teacher, mentor’s feedback and researcher’s journal reflection. Based on the data result of this research, it showed that the implementation of NHT method could increase the learning activeness of the students, even though the increasing had not attained the comprehensiveness minimum criteria that had been decided. A main principle from every step of NHT method implementing which increasing the learning activeness of the students was heads together, which means every student in a group should combine their thought to answer the questions that teacher gave and for this matter, teacher should control the class well when the students followed discussion phase from NHT method.