Henry Riley or Henry Reilly may refer to:
- Henry Riley (scientist) (1797–1848), British surgeon and naturalist, co-discovered the Thecodontosaurus
- Henry Thomas Riley (1816–1878), English translator, lexicographer, and antiquary
- Henry Chauncey Riley (1835–1904), missionary bishop
- Henry Reilly, Northern Irish politician
- Henry J. Reilly (1881–1963), American soldier and journalist