English articles have been much discussed but still leave many examples of use or non-use unexplained. This paper starts from the observation that the definite article can be replaced by the indefinite article or unexpressed, in contrast to the general assumption that it is obligatory when the semantic condition of definiteness is satisfied. It argues that definiteness should be pragmatically redefined in terms of a speaker’s intention. It further argues that English articles, as part of referring expressions, are subject to various discourse and pragmatic principles. They do not have to be explicit if hearers can understand the reference in the discourse context without being guided by them, but speakers usually opt to express in a way hearers can understand the reference most clearly, according to the cooperative principle. Also, the roles of the articles are divided by a pragmatic division of labor when they share their meanings and can be alternated with each other. This kind of discourse-pragmatic approach tends to provide a more comprehensive account of English articles, better revealing their nature as referring expressions.