This book aims to provide a better understanding of convergence and non-convergence phenomena, such as divergence, from different theoretical perspectives. It brings together nine case studies that deal with contact between languages found in the Iberian Peninsula (Castilian, Catalan, Portuguese and Basque), between Spanish or Portuguese and another language (such as English), and between different varieties from Europe and other continents. The volume thus unites views from two fields that rarely interact: contact linguistics and dialectology. It discusses the mechanisms and consequences of language contact within the Ibero-Romance world, a geographical space characterised by a high rate of multilingual speakers and settings. The contributions deal with various combinations of convergence and divergence, for example between different varieties of the same language, language stability despite contact, as well as less studied aspects, such as the relation between language contact and second language acquisition, the linguistic landscape perspective of language contact, and divergence in linguistic identity construction.