This study investigated whether Dialogue Journal Writing (DJW) could improve students' classroom participation and willingness to communicate through sustained written interaction with the teacher, drawing on a sociocultural perspective. The participants included 15 intermediate and upper-beginner EFL learners attending two private language institutes in Iran over a period of 2.5 months. To ensure a comprehensive understanding of the intervention's impact, a triangulated approach to data collection was adopted, incorporating questionnaire data, a participation rubric, semi-structured interviews, and textual analysis of journal entries. The findings revealed statistically significant improvements in both classroom participation and willingness to communicate (p < 0.05). Moreover, the journals served not only as a means of linguistic practice but also as a space for meaningful interaction and individualized feedback from the teacher, effectively fostering learners' development throughout the process.