This article presents evidence of syntactic transfer from Chinese to English based on data obtained from 710 Hong Kong Chinese ESL learners at different proficiency levels. Three methodologies were used: self-reporting in individual interviews, translation (with and without prompts), and grammaticality judgment. The focus of the study was on 5 error types: (a) lack of control of the copula, (b) incorrect placement of adverbs, (c) inability to use the there be structure for expressing the existential or presentative function, (d) failure to use the relative clause, and (e) confusion in verb transitivity. The results showed that many Chinese ESL learners in Hong Kong tended to think in Chinese first before they wrote in English, and that the surface structures of many of the interlanguage strings produced by the participants were identical or very similar to the usual or normative sentence structures of the learners' first language (L1), Cantonese. The extent of syntactic transfer was particularly large for complex target structures and among learners of a lower proficiency level, though high-proficiency learners may also have relied on the syntax and vocabulary of their previous linguistic repertoire, their L1, when finding it difficult to produce output in the target language.