Gaius Julius Eurycles or Eurycles of Sparta (b. Sparta, fl. 1st century BCE), was "hegemon of the Lacedaemonians" Λακεδαιμονίων ἡγέμων), a benefactor of Greek cities, and founder of the family of the Euryclids.
Eurycles was the son of Lachares. His father was executed on charges of piracy by Marcus Antonius. Eurycles joined forces with Octavian even before the battle of Actium. He was rewarded with Roman citizenship and the title of Λακεδαιμονίων ἡγέμων by emperor Augustus. In the late 1st century BCE, Eurycles behaved strangely and caused trouble in many Greek cities, which led to his banishing by Augustus. In the early years of Tiberius' reign, Eurycles was fully rehabilitated in Sparta.
Gaius Julius Laco was his son.