Book excerpt: The plant metabolome is highly complex, being composed of over 200,000 metabolites. The characterization of these small molecules has been crucial to study plant growth and development as well as their response to environmental changes. The potential of metabolomics in plant research, particularly if applied to crop plants, is also extremely valuable in the discovery of biomarkers and in the improvement of crop yield and quality. This Frontiers Research Topic addresses many applications of metabolomics to crop research, based on different analytical platforms, including mass spectrometry, and nuclear magnetic resonance. It comprises 13 articles from 109 authors that show the importance and the contribution of metabolomics in the analysis of crop’s traceability and genetic variation, in the study of fruit development, and in the understanding of the plant’s response to the environment and to different biotic and abiotic stresses.