盖乌斯·尤利乌斯·恺撒¹（拉丁文：Gaius Julius Caesar²，前100年7月－前44年3月15日），罗马共和国末期的军事统帅、政治家，尤利乌斯家族成员。

恺撒出身贵族，历任财务官、大祭司、**、执政官、监察官、独裁官等职。前60年与庞培（拉丁语：Pompeius；英语：Pompey）、克拉苏（Crassus）秘密结成前三头同盟，随后出任高卢总督，用了8年时间征服高卢全境（现在的法国），亦袭击了日耳曼和不列颠。西元前49年，他率军占领罗马，打败庞培，集大权于一身，实行独裁统治，制定了《儒略历》。

Gaius Julius Caesar (Classical Latin: [ˈɡaː.i.ʊs ˈjuː.li.ʊs ˈkae̯.sar]; 13 July 100 BC – 15 March 44 BC) was a Roman statesman, general, and notable author of Latin prose. He played a critical role in the events that led to the demise of the Roman Republic and the rise of the Roman Empire. In 60 BC, Caesar, Crassus, and Pompey formed a political alliance that dominated Roman politics for several years. Their attempts to amass power through populist tactics were opposed by the conservative ruling class within the Roman Senate, among them Cato the Younger with the frequent support of Cicero. Caesar's victories in the Gallic Wars, completed by 51 BC, extended Rome's territory to the English Channel and the Rhine. Caesar became the first Roman general to cross both when he built a bridge across the Rhine and conducted the first invasion of Britain.