Body of Abstract: Drought is one of the most serve abiotic stresses affecting seed germination and seedling development. Enhancing seed germination under limited water conditions will greatly improve stand establishment in agricultural settings and ultimately improve crop yield. Barley (Hordeum vulgare L.) is considered a hardy cereal and exhibits a wide range of responses to drought. In this study, 165 spring barley accessions from the USDA iCore collection, representative of a globally distributed population, were subjected to a polyethylene glycol (PEG)-induced drought. For each accession 30 seeds were assessed for their germination over a five-day period in PEG (20% w/v) or water, in glass petri-plates. Germination rate (GR) and germination pace (GP) were recorded, and four additional derived traits were calculated. To evaluate seedling development, accessions were grown in germination paper tubes in PEG (20% w/v) or water for seven days. Seedings were phenotyped using a winRHIZO scanner and software recording root length and surface area. Fresh biomass and dry weights were also recorded from seedlings. This population was genotyped using the 50K Illumina SNP array. A genome-wide association scan (GWAS) was used to identify 22 single nucleotide polymorphisms (SNPs) associated with GR, GP, and subsequent derived traits in this simulated drought treatment. Our analysis found 11 putative quantitative trait loci (QTLs) with candidate genes encoding proteins related to germination and abiotic stress. This mini-core population was phenotyped for short-term drought stress (five days) during the heading stage in a greenhouse. Seed yield, root, and shoot biomass data were recorded for droughted plants and well-watered controls. Accessions scored as tolerant in the PEG-based screening and greenhouse drought phenotyping are useful germplasm for breeding drought-tolerant barley varieties. Marker trait associations consistently identified in response to drought during germination, seedling stage, and heading provide novel target genes for enhancing climate-resiliency in crops.