This mixed methods study was designed to understand the teachers' apprehension towards the use of mother tongue as medium of instruction by determining their language beliefs, and how these influence their pedagogical practices and ultimately the implementation of the policy. The language beliefs identified from the participants' online interviews are a result of years of experience as teachers and learners themselves, The increasing demand of Filipino workers abroad may also be a factor to their apprehension since international employers mostly hire those who can communicate well in English. Also, the participants were taught in English and Filipino, which are the mediums of instruction of RBEC, BEP, and even EO 210, s. 2009, all of which targets English as the moet desirable language for learners. The participants' pedagogical practices may have also been influenced by their language beliefs. Teachers chose to introduce concepts in English and Filipino first, and then later translate them into Kapampangan, instead of teaching using the Kapampangan language, then translating into English and Filipino. The participants believe that its implementation limits students' exposure to English, which they consider beneficial to learners in the future. Consequently, because they had firsthand experience with Bilingual Education Policy, they were concerned that the MTBMLE policy would prevent their students from learning English even after graduation. They were also concerned about the lack of materials and textbooks because they had no way of knowing if they were correctly delivering and using Kapampangan in class.