This study explores the widely documented difficulty children have with object clitics in the acquisition of Romance languages. It reports on two experiments: a production task and a comprehension task. Results from the elicitation task confirm that object omission occurs at nonnegligible rates in 2- and 3-year-olds. Findings from the sentence-picture matching task show that children do not sanction a grammar with referential null objects, as suggested by previous research, and that children do not always assign a transitive interpretation to clitic constructions. Further analysis reveals that both the frequency of object omissions in production as well as the results in the clitic conditions of the receptive task are strongly negatively correlated with an independent measure of verbal working memory (nonword repetition task), consistent with the hypothesis that object clitic omission is affected by linguistic processing and short-term memory limitations.