Barclay Tagg (born December 30, 1937 in Lancaster, Pennsylvania) is an American thoroughbred horse trainer. A 1961 graduate of Pennsylvania State University with a degree in Animal Husbandry, he is best known for conditioning Kentucky Derby, Preakness Stakes, and Jockey Club Gold Cup winner Funny Cide. Horses in Tagg's stable have included Showing Up and Nobiz Like Shobiz.