"Doctor Know-all" (German: Doktor Allwissend) is a German fairy tale collected by the Brothers Grimm, tale number 98 in Grimms' Fairy Tales.
The folktale is widespread "throughout Europe, India,[1] Asia, some parts of Africa" and in the Americas.
[2] Commenting on the tale repertoire of female storyteller Argyro, a Greek refugee from Asia Minor, Greek scholar Marianthi Kaplanoglou stated that she knew a story of the tale type ATU 1641, a "common" type to both "the Greek and Turkish corpora".
[3] German scholar Ulrich Marzolph [de], in his catalogue of Persian folktales, listed 10 variants of the tale type across Persian sources, with the title Der falsche Wahrsager ("The False Soothsayer").
[4] According to Professor Bronislava Kerbelytė [lt], the tale type is reported to register 229 Lithuanian variants, under the banner Doctor Know-All.