色雷斯（希腊语：Θρᾴκη，保加利亚语：Тракия，土耳其语：Trakya）是东欧的历史学和地理学上的概念。今天的色雷斯包括了保加利亚南部（北色雷斯）、希腊北部（西色雷斯）和土耳其的欧洲部分（东色雷斯）。色雷斯濒临三个海，分别是黑海、爱琴海和马尔马拉海。在土耳其，它也被称为鲁米利亚（Rumeli）。

希腊北部西色雷斯为希腊东马其顿和色雷斯大区的一部分，称色雷斯地区，辖埃夫罗斯州、克桑西州、罗多彼州。

东色雷斯面积24,476km²，西色雷斯面积8,578km²，北色雷斯面积42,155km²。

历史上色雷斯的边界经常发生变化。古色雷斯（即古色雷斯人居住的地域）包括了现在的保加利亚、土耳其的欧洲部分、希腊东北部、塞尔维亚东北部的一部分以及马其顿共和国的东部，北至多瑙河，南濒爱琴海，东至黑海与马尔马拉海，西达瓦达河和大摩拉瓦河。而作为罗马行省的色雷斯面积则相对较小，北部边界退至了巴尔干山脉，西部边界则位于美斯塔河。

Thrace /ˈθreɪs/ (demonym Thracian /ˈθreɪʃⁱən/; Ancient Greek: Θρᾴκη, Thrāikē; modern Greek:Θράκη, Thráki; Bulgarian:Тракия, Trakiya Turkish:Trakya) is a historical and geographic area in southeast Europe, centered on the modern borders of Bulgaria, Greece, and Turkey. In antiquity, it was also referred to as Europe, prior to the extension of the term to describe the whole continent. As a geographical concept, Thrace designates a region bounded by the Balkan Mountains on the north, Rhodope Mountains and the Aegean Sea on the south, and by the Black Sea and the Sea of Marmara on the east. The areas it comprises are southeastern Bulgaria (Northern Thrace), northeastern Greece (Western Thrace), and the European part of Turkey (Eastern Thrace). The biggest part of Thrace is part of present-day Bulgaria. In Turkey, it is also called Rumeli. The name comes from the Thracians, an ancient Indo-European people inhabiting Southeastern Europe.