Gnaeus Servilius Geminus (died August 2, 216 BC) was a Roman consul, serving as both general and admiral of Roman forces, during the Second Punic War.
The son of Publius Servilius Geminus, Gnaeus Geminus was elected as consul in early 217 BC. By March of that year, Geminus began directing military operations against the Carthaginian General Hannibal Barca around Ariminum. Following the death of the consul Gaius Flaminius Nepos at the Battle of Lake Trasimene (Trasimeno) in April (as well as the rise to power of dictator Fabius Maximus the following month), Geminus assumed command of the Roman fleet overseeing coastal defense and battles against Sardinia, Corsica and the North African coast.
In November, Geminus resumed command of Roman land forces and, having been elected proconsul in early 216, became involved in skirmishes with approaching Carthaginian forces under Hannibal from March until May, before he was killed while in command of the center of the Roman line during the Battle of Cannae on August 2, 216 BC.