Xiāo Jí 蕭吉 (zì Wénxiū 文休; d. 614) was a Suí-dynasty 隋 court specialist in yin-yang, the five phases, and the calendar, and the most prolific surviving theorist of correlative cosmology of his era. He was a native of Lánlíng 蘭陵 and descended from the imperial Xiao 蕭 clan of the Southern Liáng 梁 (a great-great-grandson of Liáng Wǔdì 梁武帝 in the standard genealogical reckoning); after the fall of the Liáng he migrated north and took service first under the Northern Zhōu 北周 and then under the Suí. He held a series of posts attached to the Tàicháng 太常 and to ritual / astronomical bureaus and was repeatedly consulted on matters of prognostication, calendrical reform, and imperial omens by both Suí Wéndì 隋文帝 and Suí Yángdì 隋煬帝; his biography in Suíshū 隋書 78 (列傳第四十三, 藝術) records several of these consultations in detail, including his successful prediction of the deaths of the Empress Dúgū 獨孤皇后 and of Wéndì himself.
The Suíshū bibliography credits Xiāo with multiple works on five-phases theory, divination, mortuary geomancy, and dream interpretation; of these only the Wǔxíng dàyì 五行大義 KR3g0052 survives intact, and only by way of Japanese transmission. He is occasionally confused in later sources with a homonymous Míng-dynasty figure recorded in the local CBDB dump (CBDB persons 492898 and 332533, both 明), with which he has no connection — no confident match for the Suí Xiāo Jí is available in the local CBDB sqlite dump, and the cbdbId field is therefore left blank.