A Content-Based Instruction (CBI) curriculum is centred around a core subject matter, utilizes authentic language and texts, and is tailored to meet learner needs. This approach entails acquiring communicative competence within the context of learning specific topics within that subject area. In 2017, TELTA and the Peace Corps, under the auspices of the US Embassy in Tanzania, conducted a workshop for teachers in Tanzania to provide them with skills related to CBI. The training took place in Morogoro, with over 50 local teachers and some Peace Corps volunteers in attendance. The participants were subject teachers, other than English language teachers, who utilize the English language to deliver their materials. CBI has greatly contributed to the advancement of English language education in schools. Teachers who underwent training have shown significant improvements in their teaching methods. TELTA considers CBI as a game-changer, as through this program, teachers have demonstrated improvements in their teaching approaches as well.