In the context of the fundamental and comprehensive current reform of education in Vietnam, the need of determining the basic theories of education as well as the teaching and learning models has significantly grown. At the beginning of the 21st century, constructivism-based pedagogies have been carried into Vietnamese education through a model entitled Vietnamese Escuela Nueva (VNEN). Accordingly, a profound deployment of the constructivism-based pedagogical reform was required with the aim to establish learners’ competences rather than merely providing knowledge to them as was done in the traditional education. Whereas the competence-based curriculum aligned with the constructivist pedagogy has become a hectic preparation of the education reform in Vietnam, teachers’ beliefs toward the constructivism-based teaching and learning approach have attracted educators’ attentions. This research comprises four studies as follows.The first study is to explore the Vietnamese primary-school teachers’ beliefs regarding self-study textbooks of the VNEN project, in order to determine to what extent the teachers think the textbooks support them to implement the constructivist pedagogies in Vietnamese language instruction. The results revealed inconsistence in the teachers’ beliefs toward roles of the targeted textbooks in directing teaching and learning activities. The mismatches between the VNEN textbooks and their original versions were also explored. Finally, the strengths and shortcomings of contents and physical quality of the textbooks were collected and used as bases for improving their quality.The second study aims at investigating Vietnamese primary teachers’ beliefs on the dialectical constructivist pedagogy that is approved by Vietnamese Ministry of Education and Training (MoET) through the VNEN-based reform. The study found out a tendency of a simplified interpretation, even far difference from the original pedagogical intentions of the dialectical constructivist approaches. In addition, an inconsistence was unfolded between what the teachers thought about the constructivism-based instruction and what they actually implemented in their classroom. The follow-up interviews about the classroom observations provided the reasons and understandings that are responsible for the mismatch between their expressed beliefs and their teaching practices.In the third study, we a step forward in designing a constructivism-aligned instructional model in order to accommodate the dialectical constructivist features into the Vietnamese language instruction. This study focuses on describing the design of a formal model in which core features of dialectical constructivist pedagogies are synthesised with essential aspects of Vietnamese education and culture. The designed model was deployed in six lessons in Reading and used in the following experimental study.Through a fourth study, the feasibility of the dialectical constructivist-aligned model of teaching primary Vietnamese language was validated and evaluated through an experimental study. The teachers’ teaching practices showed meaningful changes for a traditional way of learning to a more dialectical constructivist way. Concurrently, the experiment had a positive impact on the pupils’ reading competences and their high-level thinking. In addition, the teachers’ perceptions about the dialectical constructivist-aligned lessons as well as their proposition for adjusting the designed model were collected. The challenges of the model implementation in Vietnamese culture and education were perceived and discussed by the teachers. Finally, the pupils also showed their positive attitudes toward the designed lessons. This experimental study brought opportunities to improve the constructivist-aligned model and enhance the quality of teaching Vietnamese language at primary education in order to meet the new requirements of the current pedagogical reform in Vietnam.