Reilly, Ace of Spies is a 1983 British television programme dramatizing the life of Sidney Reilly, a Russian-born adventurer who became one of the greatest spies ever to work for the United Kingdom and the British Empire. Among his exploits, in the early 20th century, were the infiltration of the German General Staff in 1917 and a near-overthrow of the Bolsheviks in 1918. His reputation with women was as legendary as his genius for espionage.

The series was written by Troy Kennedy Martin, and based on the 1967 book Ace of Spies by Robin Bruce Lockhart, whose father R. H. Bruce Lockhart was one of Reilly's fellow spies. Sam Neill stars as the eponymous character. The theme music is the romance movement from Dmitri Shostakovich's The Gadfly Suite, though Shostakovich is not actually credited (Harry Rabinowitz is credited with the music).