Yú Zhīgǔ 余知古 (fl. Wénzōng 文宗 reign, 827–840) was a late-Táng literary scholar whose native place is unknown. He is recorded by the Xīn Tángshū “Yìwén zhì” as a man of the Wénzōng era. He held the title of Court Gentleman for Comprehensive Duty, Examining Editor of the Heir Apparent (jiāngshì láng shǒu tàizǐ jiàoshū 將仕郎守太子校書). He was a member of the Wénzōng-era literary circle that produced the Hànshàng tíjīn jí 漢上題襟集 in 10 juǎn, co-authored with Duàn Chéngshì 段成式 and Wēn Tíngyún 溫庭筠 (a poetry-exchange anthology, now lost). His one substantial historiographical work is the Zhǔgōng jiùshì 渚宮舊事 KR2e0007, a JīngChǔ regional history in 10 juǎn (5 juǎn surviving), almost certainly composed during his time on the Hàn River. Chén Zhènsūn 陳振孫’s Shūlù jiětí mistakenly classifies him as a Hòu Zhōu (post-Táng) figure; the Wénxiàn tōngkǎo citation of Cháo Gōngwǔ further drops the character “Yú” from his name, giving “Zhīgǔ” alone. The Sìkù compilers correct both errors.