格拉提安（格拉典）（Flavius Gratianus，359年－383年），罗马帝国西部的皇帝（375年至383年在位）。

格拉提安是西罗马帝国的皇帝华伦提尼安一世的长子，375年，在同夸迪人的战争中，华伦提尼安一世突然发病而猝，于是格拉提安在高卢即位，年仅17岁，同时，也有军队支持格拉提安的同父异母弟弟华伦提尼安二世（当时年仅4岁）即位，不过格拉提安答应与华伦提尼安二世分享帝国，将意大利、北非和伊利里亚西部交给华伦提尼安二世统治，自己保留了高卢、西班牙和不列颠。

377年，罗马帝国爆发了哥特人的大规模动乱，格拉提安准备去援助东部，但是高卢发生了阿勒曼尼人的入侵，格拉提安虽然成功地打败了阿勒曼尼人，但却因此延误了援助东部的时间。378年，东部的罗马军队在亚得良堡战役（battle of Adrianople）中遭到惨败，皇帝华伦斯阵亡。格拉提安火速赶赴救援，为了能够平定哥特人之乱，他册立极具将才的狄奥多西一世为东部的罗马皇帝。后来的事件正明了他的正确选择。此后，格拉提安返回西部，将东部帝国交由狄奥多西一世统治。

For other figures with this name, including his paternal grandfather, see Gratian (disambiguation).

Gratian (/ˈɡreɪʃən/; Latin:Flavius Gratianus Augustus; 18 April/23 May 359 – 25 August 383) was Roman emperor from 375 to 383. The eldest son of Valentinian I, during his youth Gratian accompanied his father on several campaigns along the Rhine and Danube frontiers. Upon the death of Valentinian in 375, Gratian's brother Valentinian II was declared emperor by his father's soldiers. In 378, Gratian's generals won a decisive victory over the Lentienses, a branch of the Alamanni, at the Battle of Argentovaria. Gratian subsequently led a campaign across the Rhine, the last emperor to do so, and attacked the Lentienses, forcing the tribe to surrender. That same year, his uncle Valens was killed in the Battle of Adrianople against the Goths – making Gratian essentially ruler of the entire Roman Empire. He favoured Christianity over traditional Roman religion, refusing the divine attributes of the Emperors and removing the Altar of Victory from the Roman Senate.