Indonesian students face the challenge of writing good journal articles, much of which is due to a lack of appropriate writing skills. The current study aimed to find out the difference between writing journal articles through thematic learning models or conventional learning models, as well as using each of these models with or without textbooks. This study used a 2x2 factorial design as a quasi-experiment and assigned 160 students as a sample and used four treatments. Data were analyzed using a two-way ANOVA p=0.05. Results showed that (1) students who were taught using thematic learning models without text books had a significantly different mastery of writing journal articles than those taught through conventional learning models using textbooks. This study elaborated how IMRAD (Introduction, Methods, Results and Discussion) model for article writing could be performed on students. The study thus concluded that a theme-based approach was better than conventional approach in teaching writing. The study also helped discover internal factors such as intelligence, motivation, interest and passion, and the external factors that include teachers' guide, sample writing, learning models and use of textbook. The study recommends evaluating the subject of thematic writing in a greater dimension or to conduct a content analysis to derive an in-depth analysis of the structure of journal article writing.