This study addresses research gaps in predicting second language (L2) writing proficiency using linguistic features. Key to this analysis is the inclusion of linguistic measures at the surface, textbase and situation model level that assess text cohesion and linguistic sophistication. The results of this study demonstrate that five variables (lexical diversity, word frequency, word meaningfulness, aspect repetition and word familiarity) can be used to significantly predict L2 writing proficiency. The results demonstrate that L2 writers categorised as highly proficient do not produce essays that are more cohesive, but instead produce texts that are more linguistically sophisticated. These findings have important implications for L2 writing development and L2 writing pedagogy. (Contains 7 tables.)