Working abstract Young children are known to excel at pragmatic inferences known as ad hoc quantity implicatures, inferring, for example, that “the card with apples” is the card with only apples. However, it is not known whether children take into account the speaker’s perspective in deriving such inferences, as adults are able to do, and as received theories of pragmatics claim. In two experiments, we tested children (5-7 years, N = 33 and N = 25) and adults using a picture-matching director task, and found that adults can both derive implicatures when all information is in common ground and not derive them when relevant information is in privileged ground, while children also derive ad hoc implicatures when relevant information is in common ground but, crucially, fail to not derive them when it is in privileged ground. Children’s difficulty to integrate perspective-taking with pragmatic inferencing challenges the received pragmatic theories. NB Data were collected under a permissions agreement, current at the researcher's institution in 2013, that only allowed release of group data.