The Tale of Igor's Campaign or The Tale of Ihor's Campaign is an anonymous epic poem written in the Old East Slavic language. The title is occasionally translated as The Tale of the Campaign of Igor, The Song of Igor's Campaign, The Lay of Igor's Campaign, The Lay of the Host of Igor, and The Lay of the Warfare Waged by Igor.

Old East Slavic was a language used by the East Slavs from the 7th or 8th century to the 13th or 14th century, until it diverged into the Russian and Ruthenian languages. Ruthenian eventually evolved into the Belarusian, Rusyn, and Ukrainian languages.