Commonly known as "Kissing Spines" (KS), the pathological mechanisms underlying impingement and overriding of spinous processes (ORSPs) in horses are poorly understood. Thoroughbreds, Warmbloods, and stock-type breeds, including Paint Horses and Quarter Horses are at increased risk for developing clinical signs of KS. A total of 155 stock-type and Warmblood horses presented at collaborating veterinary clinics and hospitals were examined using a strict clinical and radiographical phenotyping scheme to grade each horse from 0 for unaffected controls to 4 for severe KS. Following genotyping with the Illumina Equine SNP70 array (Illumina, Inc.) a Genome Wide Association Study (GWAS) using 61,229 filtered individual Single Nucleotide Polymorphisms (SNPs) was performed to the KS grade phenotype. Two significantly associated SNPs (BIEC2-668062 and BIEC2-668013) on chromosome 25 defined a ~1.4 Gb candidate region containing approximately 17 coding genes (EquCab3) and 195 ENSEMBL annotated variants. Investigation of the best associated SNP (BIEC2-668062) on chr25 demonstrates a significant correlation with an increase in one KS grade, on average, per A allele in this population. A significant effect of breed group, age, height or sex was not observed in this population. These preliminary results demonstrate the potential for KS diagnosis and preventative measures for WB/ST individuals supported by increased genetic risk for more severe KS grade. We propose further research including other affected breeds and evaluating causative variants, as well as the effect of BIEC2-668062 in these populations.