Keaktifan merupakan salah satu prinsip belajar yang harus dimiliki oleh siswa pada kegiatan pembelajaran di dalam kelas, termasuk di dalam kegiatan pembelajaran biologi. Namun, berdasarkan penelitian yang dilakukan di kelas VIII SMP ABC, peneliti menemukan bahwa siswa pasif dalam hal memperhatikan penjelasan guru maupun mengajukan dan menjawab pertanyaan yang guru ajukan. Games merupakan salah satu metode pengajaran yang dapat digunakan oleh guru untuk meningkatkan keaktifan belajar siswa. Maka pada penelitian ini, peneliti ingin meningkatkan keaktifan belajar siswa melalui penggunaan games pada pembelajaran biologi kelas VIII SMP ABC. Metode penelitian yang digunakan peneliti adalah penelitian tindakan kelas (PTK). Adapun instrumen yang digunakan adalah lembar observasi mentor dan guru pelajaran biologi, angket siswa, dan jurnal refleksi peneliti. Penelitian dilakukan sebanyak dua siklus. Peneliti menemukan adanya peningkatan keaktifan belajar siswa dari perbaikan pelaksanaan games. Games yang dirancang peneliti berdasarkan indikator games yang baik yaitu fun to play, easily adaptable, challenging, dan student-centered. Adapun peningkatan keaktifan dalam penelitian ini yaitu keaktifan siswa dalam memperhatikan penjelasan guru (visual activities) dan keaktifan siswa dalam bertanya maupun mengemukakan jawaban dari setiap pertanyaan yang diajukan guru (oral activities). / Activeness is one of the study principle that must be possessed by the students on learning activity in the class, included the learning of biology. However, based on the research that had done in grade VIII of ABC Junior High School, the researcher found that the students were passive in giving their attentions to teacher’s explanation as well as asking or answering the questions(s) that the teacher asked. Games is one of teaching method that can be used by the teacher to improve students’ learning activeness. Therefore, on this research the researcher wanted to improve students’ learning activeness through the using of games on the learning of biology at grade VIII in ABC Junior High School. Research method that used by the researcher was Classroom Action Research (CAR). The instruments that the researcher applied were mentor and biology teacher observation sheet, student questionnaire, and researcher reflection journal. The research has done by the term of two cycles. The researcher found that there was an improvement on students’ learning activeness of games activities. The games were designed by the researcher based on a good game indicator which are: fun to play, easily adaptable, challenging, and student-centered. The improvement itself involved students’ activeness in giving attention to teacher’s explanation (visual activities), and students’ activeness in asking and giving answer of each question teacher asked (oral activities).