Abstract. This study offers a comprehensive investigation into the extent to which peer assessment contributes to the development of speaking communication skills among English as a Foreign Language (EFL) learners. Employing a quasi-experimental design, the research involved 60 university-level EFL students who were systematically assigned to either an experimental group or a control group. Over an eight-week intervention period, the experimental group participated in a series of structured peer-assessment cycles in which learners evaluated one another’s speaking performances using criterion-referenced rubrics and guided feedback protocols. In contrast, the control group engaged in the same speaking tasks but received only traditional instructor-provided feedback. Multiple data sources—including pre- and post-instruction speaking tests, learner-perception questionnaires, and weekly reflective journals—were triangulated to gather both quantitative and qualitative evidence. The findings revealed a marked and statistically significant improvement among the experimental group across key dimensions of oral competence, specifically fluency, coherence of ideas, communicative confidence, and strategic use of language. Learners who engaged in peer assessment not only demonstrated stronger post-test performance compared to their control-group counterparts but also displayed heightened metacognitive awareness, greater self-regulation, and increased motivation to improve their speaking proficiency. Qualitative analyses further indicated that the peer-assessment process fostered deeper engagement with speaking tasks, encouraged critical listening, and cultivated a more collaborative learning environment. Taken together, these results suggest that peer assessment functions as a powerful pedagogical mechanism for enhancing speaking communication skills in EFL contexts. Beyond serving as an alternative assessment strategy, it operates as a formative learning tool that empowers students to internalize performance criteria, refine communicative strategies, and take greater ownership of their oral language development. The study underscores the pedagogical value of incorporating structured peer-feedback practices into language curricula and offers implications for designing more interactive, learner-centered approaches to speaking instruction.