Scientific competence is essential in preschool education as it fosters foundational thinking and problem-solving skills, paving the way for children’s engagement with STEM fields. Young children are naturally inquisitive, and early exposure to scientific thinking helps nurture observation, questioning, and experimentation abilities. However, many current preschool curricula, including in Vietnam, lack a clear framework for developing and assessing scientific competence. This study proposes a conceptual framework to integrate science education systematically into preschool programs. Using literature review, content analysis, and the Delphi method, the study identifies five core components of scientific competence: critical thinking, experimental thinking, observation skills, questioning skills, and problem-solving. These elements reflect key scientific abilities children can acquire through exploration and guided activities. The proposed framework offers practical tools for teachers to design and evaluate science-based learning. Future studies should implement this framework in real classroom settings to assess its effectiveness and refine it for better applicability in Vietnam’s preschool context.