Topic and topicalization are key notions to understand processes of syntactic and prosodic readjustments in Romance. More specifically, topicalization refers to the syntactic mechanisms and constructions available in a language to mark an expression as the topic of the sentence. Despite the lack of a uniform definition of topic, often based on the notions of aboutness or givenness, significant advances have been made in Romance linguistics since the 1990s, yielding a better understanding of the topicalization constructions, their properties, and their grammatical correlates. Prosodically, topics are generally described as being contained in independent intonational phrases. The syntactic and pragmatic characteristics of a specific topicalization construction, by contrast, depend both on the form of resumption of the dislocated topic within the clause and on the types of topic (aboutness, given, and contrastive topics). We can thus distinguish between hanging topic (left dislocation) (HTLD) and clitic left-dislocation (ClLD) for sentence-initial topics, and clitic right-dislocation (ClRD) for sentence-final dislocated constituents. These topicalization constructions are available in most Romance languages, although variation may affect the type and the obligatory presence of the resumptive element. Scholars working on topic and topicalization in the Romance languages have also addressed controversial issues such as the relation between topics and subjects, both grammatical (nominative) subjects and ‘oblique’ subjects such as dative experiencers and locative expressions. Moreover, topicalization has been discussed for medieval Romance, in conjunction with its alleged V2 syntactic status. Some topicalization constructions such as subject inversion, especially in the non-null subject Romance languages, and Resumptive Preposing may indeed be viewed as potential residues of medieval V2 property in contemporary Romance.