African Folk Tales
CanTeach
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Bura folktales.
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South African Folk Tales Index

American Folklore
Retellings of American folktales, Native American myths and legends.
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American Folklore Society
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Native American Lore Index

Hans Christian Andersen:
Fairy Tales and Stories - from the English Translation: H. P. Paull 

Arabian Nights
An Annotated Index
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Arabian Nights
Wikipedia entry.

Celtic legends

China

Ancient Chinese Fables
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Chinese folk tales.

Eastern Stories and Legends,
re-told by Marie L. Shedlock.
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English fairy tales.
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Europäische Märchengesellschaft. The European Fairy-Tale Society
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F

Fairy Tales,
an index from The University of Maryland.
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Fairy Tales. SurLaLune.
A portal to the realm of fairy tale and folklore studies featuring 35 annotated fairy tales, including their histories, similar tales across cultures, and over 1,200 illustrations. Discover hundreds of fairy tales from around the world.
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Festivals

Folklore and Mythology Electronic Texts
The University of Pennsylvania
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Folk and Fairy Tales from Around the World
An archive of folk and fairy tales. 
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Folklore and Mythology
Electronic Texts edited and/or translated by D. L. Ashliman, University of Pittsburgh.
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The Folklore Society, U.K.

Grimm's Fairy Tales. Complete texts.

Grimm Fairy Tales,
an interactive website.
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Grimm Fairy Tales,
an animated site from National Geographic.
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Die Brüder Grimm. Nineteenth Century German Stories
Web editions for language learning & literary study.

Hungarian Folklore. American Hungarian Folklore Centrum

A Flowering Tree and other Oral Tales from India.
A. K. Ramanujan.

Indiana University Folktales Collection
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Ireland

Irish Fairy Tales -
etexts from Project Gutenberg.
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Irish Folk Tales

Marvels and Tales. Journal of Fairy-Tale Studies

Norwegian Folk Tales

Persian Folk Tales for Children

Romanian Folk Tales

Russian and Ukrainian Folktales

South American Folktales and Fairytales