Academic literacy is an embodiment of higher order thinking and learning within the academic community and bears huge significance for individual language socialization, resource distribution and power disposition within the societies. Previous research suggests that academic literacy development is multidimensional, involving both language, cognition and rhetorical genre skills (Flowerdew, 2013; Uccelli et al., 2015). However, to date few of them focused on the interaction among the three aspects in concrete teaching and learning practices. The study adopts a mixed methods approach to analyze a cohort of undergraduate EFL learners’ academic writing samples in terms of their written language complexity, accuracy, cognitive sophistication and rhetorical genre skills (Kuhn & Crowell, 2011; Lu, 2010, 2012; Swales, 1990). Results reveal that 1) EFL learners are generally weak in dual and integrative perspective taking in academic writing regardless of their language proficiency levels; 2) content complexity and cognitive complexity are a possible underlying driving force for language complexity despite a trade-off effect for accuracy; and 3) among all measures, written language accuracy and cognitive complexity are two significant predictors for EFL learners’ language proficiency. Results show that the development of language, cognition and rhetorical genre skills are mutually interrelated. Understanding their interactions can shed light on an authentic and integrated pedagogy that promotes L2 learning while also attending to the role of explicit instruction in accuracy development.