Rocket (Eruca spp. and Diplotaxis spp.) is widely cultivated as a green vegetable in Mediterranean countries, Europe, United States and Brazil, but few rocket cultivars are available and limited variety selection has taken place. Plant genetic resources and germplasm are fundamental sources for plant breeding, and the assessment of the genetic diversity among germplasm accessions is useful to facilitate the more efficient use of plant genetic resources. The objective of this study was to characterize phenotypic diversity and relationships among genotypes of Eruca and Diplotaxis originating from 11 countries across three regions (Europe, Africa and Asia). Principal component analyses explained over 85% of total variation for 51 qualitative and quantitative agromorphological traits. Cluster analyses divided the accessions into five major clusters according to plant traits, siliqua properties and geographical origin of genotype with a few exceptions. These findings indicate a number of useful traits in the gene pool and a wide range of phenotypic variation that provides a good source of diversity for use in modern Eruca breeding programmes.