The aim of this paper is to examine Differential Object Marking (DOM) in Balearic Catalan. While definiteness and animacy can explain the distribution of DOM in other varieties of Catalan, in Balearic, the split between marked and non-marked objects is not dependent on inherent or referential properties of the object noun phrases, but determined by topicality. A preposition is consistently used to mark a subset of topical objects, namely those occurring in clitic left- and right-dislocation structures, which correspond to two kinds of hearer-known topics: shifting topics and continuing topics. The preposition does not occur, however, with hanging topics, which introduce discourse-new topical entities. In this way, a correlation can be found between formal properties and well-motivated discourse functions that explains the distribution of DOM in Balearic. Similar patterns can be found in other Romance varieties as well, thus suggesting that topicality is relevant to account for both intra- and interlinguistic variation in DOM.