Communication skill is considered to be one of the most demanding skills of the day, and proficiency in listening and speaking skills paves the way for being communicative. To develop one’s listening and speaking skills, there are many ways and factors including the use of audiovisual materials in an English as a foreign language (EFL) classroom. This study analyzed the effectiveness of audiovisual materials in developing tertiary level students' English listening and speaking skills. To do so, experiments followed by formative assessment were carried out on the first-year undergraduate students of the Department of English, Jashore University of Science and Technology, Bangladesh. To triangulate the experiment results and ensure trustworthiness, a student-questionnaire survey was also conducted. The overall findings revealed that the use of audiovisual materials has a major impact on the development of listening and speaking skills of EFL students. The findings of this research are supposed to help education policymakers, education administrators, teachers, and students to adopt better policies and decisions to make teaching and learning English more effective and fruitful at different stages in second or foreign language contexts.