This volume comprises sixteen peer-reviewed selected papers presented at the 45 th Linguistic Symposium on Romance Languages (LSRL), that took place on May 6–9, 2015, at the University of Campinas, Brazil. United by a common goal – the formal analysis of Romance languages –, these papers focus on a wide range of topics in different areas of grammar (phonology, morphology, syntax, semantics, pragmatics, plus interfaces), and in different research domains (L1 grammar, L2 acquisition, variation and change, bilingualism and language contact, code-switching). The Romance languages represented in this volume include Peninsular and American Spanish; European, Brazilian and Mozambican (Maputo) Portuguese; French; Italian and Italian dialects (especially Borgomanerese); and Palenquero, a Spanish-based creole. Most papers assume a comparative approach to the discussed topics. Overall, the papers present new data and new approaches to familiar structures, as well as new developments for less known phenomena.