Why do we observe Shavuot by studying all night?

Answered by
George Robinson

Since the Rabbinic period, Shavuot has been tied to the story of receiving the Torah. Connected to this, Shavuot has come to be dedicated to the idea of Torah study and Jewish education. One custom is an all-night [or late night] study session held on the first evening of the festival, called tikkun leil Shavuot. This custom, which had its beginning in the community of kabbalists centered around sixteenth-century Safed, is designed to prepare Jews for “receiving” the Torah again on Shavuot.

See also: 
What is a Confirmation?
Tikkun Leil Shavuot Videos and Study Guides

George Robinson is the author of the critically acclaimed Essential Judaism: A Complete Guide to Beliefs, Customs and Rituals (revised edition, Atria Books, 2016) and Essential Torah: A Complete Guide to the Five Books of Moses (Schocken Books, 2006). Mr. Robinson is the film critic for The Jewish Week, the largest Jewish newspaper in North America, and a frequent contributor to Hadassah Magazine. He is adjunct assistant professor of media studies at Borough of Manhattan Community College, and has been critic-in-residence at several Jewish film festivals around the country. Robinson was a contributor to the recent edition of Encyclopedia Judaica and has written frequently for The New York Times, The Washington Post, Newsday, Kirkus Reviews, and Publishers Weekly. Mr. Robinson lives in New York City with his wife Margalit Fox, a reporter for the New York Times and an author in her own right.