Shiraz University Teaching English as a Second Language Quarterly 2981-1546 45 3 2026 06 01 Online Synchronous/Asynchronous Vs In-person Mediation and EFL Learners' Writing Skills Development 1 22 8293 10.22099/tesl.2025.53553.3430 EN Elham Pourrasa Department of Applied Linguistics and TEFL, Payame Noor University, Tehran, Iran Hassan Soleimani Department of Applied Linguistics and TEFL, Payame Noor University, Tehran, Iran Maryam Farnia Department of Applied Linguistics and TEFL, Payame Noor University, Tehran, Iran 0000-0001-7046-6533 Fatemeh Takallou Department of Applied Linguistics and TEFL, Payame Noor University, Tehran, Iran Journal Article 2025 07 07 <strong>As the demand for effective language instruction continues to rise in an increasingly digital world, understanding the impact of different synchronous/asynchronous mediation methods on language acquisition is crucial. Drawing on Vygotskian sociocultural theory and social constructivism, and adopting a quasi-experimental approach, this study explored the impact of synchronous, asynchronous, and in-person mediations on short- and long-term general writing skills through one-on-one dynamic assessment sessions conducted in-person and online using ONLYOFFICE Personal and its upgraded version, ONLYOFFICE DocSpace. Moreover, it explored the perceptions of synchronous and asynchronous online learners regarding computer-assisted language learning using a Likert-scale questionnaire. Sixty EFL university students preparing for the IELTS General exam participated in the study. Their general writing skills were assessed using IELTS Task 1 samples from three books, and they were marked according to the IELTS band descriptors. To analyze the data, Kruskal-Wallis and Chi-Square tests were used. The findings revealed that in-person mediation was significantly more effective than both online mediations in the short run. No significant difference was found between online synchronous and asynchronous mediation in the short term. However, online synchronous mediation proved more effective than its asynchronous counterpart in the long term, though not significantly different from in-person mediation. In addition, the results showed that students in synchronous online classes displayed more favorable attitudes than those in asynchronous online classes. The study suggests that tailored mediation approaches can enhance EFL learners' writing proficiency across diverse educational contexts, offering educators and curriculum developers valuable insights.</strong> https://tesl.shirazu.ac.ir/article_8293_1c66c1d28a314d3714455b9ff78ddbf7.pdf