This paper adopts the Integrated Contrastive Model (Granger 1996) to an examination of the use of articles in the L2 English written production of L1 speakers of three article-less languages (Mandarin Chinese, Korean and Thai) across four L2 proficiency levels. Data is sourced from the International Corpus Network of Asian Learners of English (ICNALE; Ishikawa 2011, 2013), comprising 575 written essays totalling 125,588 words across two writing prompts. Accuracy of zero, indefinite and definite articles is measured using Pica’s (1983) Target Language Use across Bickerton’s (1981) semantic/pragmatic article contexts (generic, specific definite, specific indefinite and non-specific indefinite). The results show two different orders of article accuracy depending on L1 background, as well as effects of writing prompt on the accuracy of certain article forms, and evidence of pseudo-longitudinal development for particular article usages as L2 proficiency increases, although not in all cases. Massive overproduction of indefinite/definite articles in generic contexts is problematic for all three L2 groups regardless of L1 background and L2 proficiency. However, Mandarin L2 English users appear to enjoy a significant advantage in L2 article accuracy over Korean or Thai L2 English users in almost all contexts of use and L2 proficiency levels, providing further potential evidence that the often reported grammaticalisation of definiteness/specificity markers in L1 Mandarin is aiding Mandarin L2 English users’ acquisition of the English article system.