Polyphenols comprise a large family of naturally occurring secondary metabolites of plant-derived foods and are among the principal micronutrients associated with the health beneficial effects of our diet. Liquid chromatography coupled to mass spectrometry (LC-MS) and, in the last few years, high resolution mass spectrometry (LC-HRMS) is playing an important role in the research of polyphenols, not only for the determination of this family of compounds in food matrices, but also for the characterization and identification of new polyphenols, as well as the classification and authentication of natural extracts in the prevention of frauds. The purpose of this review is to describe recent advances in the LC-MS and LC-HRMS analysis and characterization of polyphenols in food focusing on the most relevant applications published in the last years. Trends regarding sample treatment, chromatographic separation, mass analyzers and chemometric approaches used in the determination and characterization of polyphenols will be addressed.