This article investigates whether explicit instruction can affect second language (L2) competence in the domain of English quantifier scope. An intervention study was conducted with L1-Mandarin L2-English learners in order to examine (1) whether these learners can learn inverse scope for the structure on which they are instructed (double-quantifier configuration: "A dog scared every man"; quantifier-negation configuration: "Every sheep did not jump over the fence"); (2) whether they can correctly generalize availability of inverse scope from the configuration on which they are instructed to one on which they are not instructed; and (3) whether learners overgeneralize inverse scope to a superficially similar configuration that does not allow inverse scope. Following Schwartz (1993), generalization is taken to be a hallmark of true acquisition (= changes to linguistic competence) as opposed to learning. The results show that learners successfully learn inverse scope for the configuration on which they are instructed, but do not generalize availability of inverse scope to the other configuration. Moreover, learners instructed on double-quantifier configurations overgeneralize availability of inverse scope to island configurations such as "There is one dog which scared every man." The findings indicate that in this domain, explicit instruction does not affect linguistic competence.