Lady's Secret (April 8, 1982 – March 4, 2003) was an American Eclipse Award winning Thoroughbred racemare that was listed in the Top 100 U.S. Racehorses of the 20th Century. Lady's Secret was bred by Robert H. Spreen at Lucas Farm in Oklahoma. Spreen sold her for $200,000 to Mr. and Mrs. Eugene Klein (former owner of the San Diego Chargers), and she was prepared for racing by Hall of Fame trainer D. Wayne Lukas. She was a small horse, weighing no more than about 900 pounds.