欧克拉提德斯一世（大帝）, （希腊语：Ευκρατιδου ο Μέγας），是最为重要的巴克特里亚国王之一。统治期间约为约前170年 - 约前145年间，欧克拉提德斯篡夺欧西德莫斯王朝成为巴克特里亚国王，开创欧克拉提德斯王朝。他曾经与希腊化世界中最遥远的印度-希腊王国国王们作战，并把势力短暂伸入北印度，直到他最后被击败并撤回巴克特里亚。欧克拉提德斯曾发行一枚名声远播的大金币，它是古典时代中所发现最大的金币，因此被认为相当有地位的君主。

Eucratides I (Greek: Εὐκρατίδης Α΄; reigned c. 170–145 BC), sometimes called Eucratides the Great, was one of the most important Greco-Bactrian kings, descendants of dignitaries of Alexander the Great. He uprooted the Euthydemid dynasty of Greco-Bactrian kings and replaced it with his own lineage. He fought against the Indo-Greek kings, the easternmost Hellenistic rulers in northwestern India, temporarily holding territory as far as the Indus, until he was finally defeated and pushed back to Bactria. Eucratides had a vast and prestigious coinage, suggesting a rule of considerable importance.