The main premise of this study is that learning physics is associated with students’ cultural backgrounds. The study utilized characteristics of Culturally Responsive Teaching (CRT) as a learning phase that involved collaborative teaching, responsive feedback, modeling, and instructional scaffolding.  The objective was to determine the improvement in the generic science skills in students through Batak culture-based learning of Ethnophysics, and to analyze the application of Ethnophysics integrated into CRT to the learning of physics. This classroom action research conducted in a Senior High School in Indonesia involved a qualitative approach completed in four circles, each consisting of four stages (planning, implementation, observation, and reflection). The sample consisted of 26 students, and the research parameters included static fluid material, momentum, and impulses, sounds, and pipes. The data were collected through interviews, reflective journals, observations, and instruments of generic science skills, and analyzed descriptively. The results showed that generic science skills of students (a) increased during each meeting (b) was found in the medium category after data analysis via the n-gain test. The study concludes that the application of Ethnophysics in learning based on Batak culture improves the generic science skills of students.