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All land plants seal their above ground body parts with a lipid-rich hydrophobic barrier called the cuticle to protect themselves from dehydration and other terrestrial threats. Mutational studies in several model species have identified multiple loci regulating cuticular metabolism and development. Of particular importance are the <i>eceriferum</i> (<i>cer</i>) mutants characterized by a loss of cuticular wax. Some barley <i>cer</i> mutants, including <i>cer-x</i>, show defects in the distinctive β-diketone-enriched wax bloom on reproductive stage leaf sheaths, stems, and spikes. We exploited extensive allelic populations, near-isogenic lines, and powerful genotyping platforms to identify variation in the <i>HvWAX INDUCER1</i> (<i>HvWIN1</i>) gene, encoding a SHINE transcription factor, as underlying <i>cer-x</i>. Comparing the <i>cer-x</i> allelic <i>glossy sheath4.l</i> Bowman Near Isogenic Line BW407 to <i>cv</i>. Bowman revealed an increased cuticular permeability in tissues showing reduced accumulation of β-diketones and altered cuticular metabolic gene expression in BW407. Analyses across the barley pangenome and hundreds of exome-capture datasets revealed high sequence conservation of <i>HvWIN1</i> and two non-synonymous variants exclusive to the cultivated germplasm. Taken together, we suggest that variation in <i>HvWIN1</i> controls multiple cuticular features in barley.