The present study investigated the developmental processes which lead from a literal interpretation of idiomatic expression to the ability of comprehending and producing them figuratively. A Model of the Development of Figurative Competence was presented according to which acquisition of idioms occurs as part of the general process of language and world knowledge development. Three experiments were carried out with second- and fourth-grade children, in which comprehension tasks - Recall, Multiple Choice, Paraphrase - and a production task - Completion - were employed. The results showed that younger children are more literally oriented than older children who in turn are more idiomatically oriented and that children of both age groups found it more difficult to produce idiomatic expressions than to comprehend them.