The study investigates explicit and implicit knowledge of article semantics in 26 second language learners of English. Their first languages, Russian and Belarusian, lack articles. The research question is whether explicit knowledge, operationalised as an ability to explain what principle governs the choice between the definite and the indefinite article in a multiple-choice test, is associated with target-like use of articles in an oral, communicative task, assumed to tap mainly into implicit knowledge. No correlation between explicit and implicit knowledge, as measured with the two tasks, was found, suggesting that explicit knowledge is not necessary to acquire article semantics in this group of learners. The result is discussed within a modular, cognitive framework, and implications for teaching are considered.