Till Eulenspiegel (German pronunciation: [tɪl ˈʔɔʏlənˌʃpiːɡəl]; Low German: Dyl Ulenspegel [dɪl ˈʔuːlnˌspeɪɡl̩]) is the protagonist of a European narrative tradition. A German chapbook published around 1510 is the oldest known extant publication about the folk hero (a first edition of ca. 1510/12 is preserved fragmentarily), but a background in earlier Middle Low German folklore is likely. The character may have been based on a historical person.

Eulenspiegel is a native of the Duchy of Brunswick-Lüneburg whose picaresque career takes him to many places throughout the Holy Roman Empire. He plays practical jokes on his contemporaries, at every turn exposing vices. His life is set in the first half of the 14th century, and the final chapters of the chapbook describe his death from the plague of 1350.

Eulenspiegel's surname translates to "owl-mirror"; and the frontispiece of the 1515 chapbook, as well as his alleged tombstone in Mölln, Schleswig-Holstein, render it as a rebus comprising an owl and a hand mirror. It has been suggested that the name is in fact a pun on a Low German phrase that translates as "wipe-arse".

Modern retellings of the Eulenspiegel story have been published since the latter 19th century. The Legend of Thyl Ulenspiegel and Lamme Goedzak, by Charles De Coster (1867), transfers the character to the period of the Reformation and the Dutch Revolt; the novel's Ulenspiegel (in modern Dutch, Tijl Uilenspiegel) was adopted as a symbol by the Flemish Movement.