Language and society are closely connected and cannot be separated as a considerable impact to other. Languages impact each other when they are in contact, therefore variation or change in language is a natural consequence. Code switching is the consequence phenomena of language contact and a marked feature of a multilingual society. The aims of the study were to analize the types of code switching that used by the teacher and the students in speaking class, to explain the reasons behind the use of code switching, and to describe the students’ perception toward code switching in teaching English speaking skill used by the teacher and the students. The researcher used qualitative descriptive method. The data collection was done by applying observation, interview, and documentation. The researcher also analysed data reduction, data display, and drawing conclusions. The result of the research showed that there were three types of code-switching, the reason the teacher used code-switching and 10 students’ perceptions toward code-switching used by the teacher and the seventh-grade students at SMPN 4 Rembang. They are 50 inter-sentential code-switching, 48 intra-sentential code-switching, and 45 tag switching. The reason for using code-switching was repetition used for clarification and interjection. The student’s perception that the researcher could conclude toward the use of code-switching to help the students understand the materials, help the students active in the teaching-learning, make the students confident, help them to comprehend the teacher’s instructions, make the students’ interest to study English, make them easy to communicate with the teacher and friends during the class, and make easy for the students to do the assignment.