This article, based on a study conducted at four senior secondary schools, discusses the role of code-switching (CS) in the classroom in Botswana where the Language in Education Policy (LiEP) of 1994 states that English is the sole official language of learning and teaching (LoLT) in schools, including senior secondary schools (Government of Botswana 1994). The data were collected through lesson observations and questionnaire administration to teachers and learners. The findings indicate that Setswana (national language) is also often used; hence CS is employed as an instructional strategy because the learners are not proficient in English. However, CS has both educational benefits and drawbacks. Positively, it increases learner participation and lesson comprehension. Negatively, it does not contribute to developing the learners’ proficiency and confidence in speaking English. Its use also (inadvertently) contravenes the LiEP. However, the use of CS is inevitable because the LoLT is a foreign language for both learners and teachers.