The purpose of the current study is to examine the role of topic familiarity in the complexity, accuracy, and fluency of second language (L2) writing. Topic familiarity was operationalized as whether writers are writing about a common, everyday subject matter in relation to themselves (+ familiar) or to a group they are not familiar with (–familiar), and a learner survey was used to test the validity of the construct. A total of 123 Chinese EFL college students participated in the study, with 61 writing on a familiar topic and 62 writing on a less familiar topic. Their writing performance was analyzed for lexical complexity, syntactic complexity, accuracy, and fluency. Data analyses revealed that the students produced essays with significantly lower lexical complexity for the less familiar topic than for the familiar topic, while the performance areas of accuracy, fluency, and syntactic complexity were not affected by the degree of familiarity. The study findings are discussed in terms of their implications for task selection and sequencing for L2 teaching and assessment purposes.