The present study sought to investigate the effects of face-to-face and web-based group dynamic assessment (GDA) on the speaking skills of Iranian intermediate EFL learners. A total of 100 participants from Ariana Institute in Rasht were involved in the study, with 36 introverted and 36 extroverted learners selected based on their scores on the Oxford Placement Test (OPT) and Eysenck’s Personality test. These participants were then divided into experimental and control groups. Each experimental group, comprising 12 participants, underwent either face-to-face or web-based GDA sessions, while the control groups received traditional instruction. The research design included a pretest, 15 treatment sessions, and a posttest to assess the progress of speaking abilities among the learners. The statistical analysis, which included paired samples t-test and one-way ANOVA, indicated significant enhancements in speaking skills among the learners who participated in the experimental GDA sessions compared to those in the control groups. Notably, introverted learners in the web-based GDA group exhibited superior speaking abilities, whereas extroverted learners showed more improvement in face-to-face GDA sessions. These results have important implications for English language educators and researchers in Iran, highlighting the significant influence of GDA delivery mode on the speaking proficiency of EFL learners, particularly in relation to their introverted or extroverted traits. Such findings can offer valuable insights for pedagogical approaches and theoretical frameworks in English language teaching in Iran. Manuscript profile