Contemporary romantic relationships in adolescence and young adulthood no longer follow a linear trajectory but come to be increasingly characterized by high heterogeneity. Social networks have also constituted a new context for interaction, which has given rise to the tendency to enact behaviors characterized by uncertainty and ambiguity. This study aims at providing a framework of the existing literature contributions on the dimensions of relational uncertainty and relational ambiguity in adolescents and young adults’ romantic relationships. A state-of-art systematic review was performed on PsycInfo, Google Scholar, Scopus, and Science Direct, adopting the PRISMA statement. Through a qualitative analysis, four themes emerged from the 23 included articles: (a) the definitions of relational uncertainty and relational ambiguity, (b) the impact on the quality of the romantic relationship, (c) communicative and individual outcomes, and (d) coping strategies.