["European Journal of Education, Volume 61, Issue 2, June 2026. ", "\nABSTRACT\nThis study evaluates a 10‐week genre‐based intervention that combined model essay analysis, explicit instruction, and process‐based writing to enhance Thai undergraduates' argumentative essay performance. Informed by genre‐based pedagogy, the intervention proceeded through a structured cycle of reading, analysis, writing and reflection. The study adopted a mixed‐methods design. Quantitative data from pre‐ and post‐intervention questionnaires (N = 26) were analysed with descriptive and inferential statistics to assess perceived development across four core dimensions of writing. Results revealed significant gains in self‐perceived task response (M = 2.63–4.21), coherence and cohesion (M = 2.85–4.26), lexical resource (M = 2.69–4.29) and grammatical range and accuracy (M = 2.50–4.06), with large effect sizes (Cohen's d = 2.03–2.77; all p < 0.001). Students reported greater confidence and control in structuring ideas, using academic vocabulary, and applying complex grammar. Qualitative data from semi‐structured interviews (n = 26), focus group discussions (six groups of 4–5 participants) and reflective journals (n = 26) were subjected to deductive content analysis. Findings revealed enhanced genre awareness, improved metacognitive regulation, and stronger engagement with academic discourse. Participants described a clearer understanding of essay types, more coherent paragraphing, and a transition from surface‐level strategies toward purposeful, audience‐oriented writing. Emotional developments, including reduced anxiety and increased autonomy, were also noted.\n"]