The Triticeae Toolbox (T3) webportal hosts data generated by the Triticeae Coordinated Agricultural Project (CAP), funded by the National Institute for Food and Agriculture (NIFA) of the United States Department of Agriculture (USDA). T3 contains SNP, phenotypic, and pedigree data from wheat and barley germplasm in the Triticeae CAP integrating rapidly expanding DNA marker and sequence data with traditional phenotypic data to provide access to predictive analyses mapping genotype to phenotype and enabling breeders to select on marker data alone. T3 will also link to related genomic and crop diversity databases (GrainGenes, Gramene, PLEXdb, and GRIN) for functional analyses to identify causal polymorphisms and networks affecting phenotypes. The software and data structure for T3 were developed as part of the Barley CAP project for its database, The Hordeum Toolbox (THT), now carried forward as part of the Triticeae CAP in the T3 databases. T3 Barley holds data generated for Hordeum vulgare L. T3 Wheat holds data generated for Triticum spp. T3 Oat holds data generated for Avena. All are being enhanced in database performance, community curation and user tools. T3 contains germplasm line information, pedigree, genotype and phenotypic data from breeding programs participating in the CAP and core germplasm collections maintained by the USDA National Small Grains Collection.