This study examined the effects of content-based instruction (CBI) using food-security terminology and of learner creativity on university EFL writing achievement. A quasi-experimental 2 × 2 factorial design involved 80 students selected by cluster random sampling (20 per cell). One class received CBI and the other problem-based learning (PBL); creativity was measured with a 30-item questionnaire and dichotomized at the class median. Data were analyzed using descriptive statistics, assumption tests, two-way ANOVA, and Tukey HSD comparisons. Two-way ANOVA revealed a significant main effect of teaching method, F(1, 76) = 5.82, p = .018, partial η² = .071; a significant main effect of creativity, F(1, 76) = 4.88, p = .030, partial η² = .060; and a large, significant interaction, F(1, 76) = 37.80, p < .001, partial η² = .332. CBI produced a higher overall mean than PBL (70.95 vs. 67.40), and highly creative students outperformed less creative students (70.80 vs. 67.55). Still, the interaction was crossover: Tukey comparisons showed that CBI–high creativity (M = 77.10) exceeded every other cell, whereas low-creativity learners scored higher under PBL (M = 70.30) than under CBI (M = 64.80). Authentic food-security content can strengthen ESP writing, but differentiated scaffolding is required because the relative effectiveness of CBI and PBL is conditional on learner creativity. Keywords: content-based instruction, English for specific purposes, food security, EFL writing, learner creativity.