| Horsename: | Day Star |
| Sire: | Star Davis |
| Grandsire: | Glencoe |
| Dam: | Squeeze-'em |
| Damsire: | Lexington |
| Sex: | Stallion |
| Foaled: | 1875 |
| Country: | United States |
| Colour: | Chestnut |
| Breeder: | J. M. Clay |
| Owner: | Thomas J. Nichols |
| Trainer: | Lee Paul |
| Record: | 42: 11-7-5 |
| Earnings: | $4,050 |
| Race: | Blue Ribbon Stakes (1878) Kentucky Derby (1878) |
Day Star (1875–1893) was the winner of the 4th annual Kentucky Derby held at Churchill Downs on May 21, 1878. He was a chestnut colt that was foaled in Kentucky and was sired by Star Davis (by the successful Glencoe). His dam was Squeeze-'em who was sired by Lexington, a foundation sire of many modern Thoroughbred lineages.
Day Star won the Derby by two lengths in an official time of 2:37.25, beating the race record set by Aristides in 1875, and winning a total of $4,050.[1]
In his career, he had 42 starts, 11 wins, 7 places and 5 shows.[2]
A 1910 Daily Racing Form article states that Day Star was sold after his racing career and stood at stud on a western farm, dying at the age of 18 years in 1893.[3]