Transitional phrases are essential for achieving cohesion and coherence in English writing. However, many second-year English major students produce essays with disjointed sentences and poorly connected paragraphs at Idlib University. This research is built on Hasan and Halliday theory of cohesion (1976). It aims to investigate whether targeted learning of transitional phrases could improve students' writing quality, to identify the types of transitional phrases students used, and to explore the difficulties they encountered. A mixed-method, quasi-experimental design is used, involving 50 second-year English major students. Data are collected through pre- and post-tests, a questionnaire and semi-structured interviews. The findings reveal a significant improvement in writing quality after the intervention, with writing scores increasing by 66.8% (mean 20.08 to 34.7, sig =0 .001). Students have shown increased use of addition and contrast transitions, while concession and inference transitions have remained limited. These results highlight the importance of integrating focused training on transitional phrases into EFL writing courses. The study offers practical implications for curriculum design, including incorporating regular drills, checklists for peer review, and short assessments. Teachers should also receive training on how to model and assess transitions effectively. The findings could inform similar interventions in other academic levels or contexts. In conclusion, systematic instruction in transitional phrases enhances students’ cohesion and overall writing quality, underscoring its importance in EFL contexts.