A tallit, taleth, or tallis is a fringed garment worn as a prayer shawl by religious Jews. The tallit has special twined and knotted fringes known as tzitzit attached to its four corners. The cloth part is known as the beged ("garment") and is usually made from wool or cotton, although silk is sometimes used for a tallit gadol.

The term is, to an extent, ambiguous. It can refer either to the tallit katan ("small tallit") item worn over or under clothing (commonly referred to as "tzitzit"), or to the tallit gadol ("big tallit") worn over the outer clothes during Shacharit—the morning Jewish prayer service—and all of the Yom Kippur prayer services. The term "tallit" alone typically refers to the tallit gadol.

There are diverse traditions regarding the age at which a tallit gadol is first used, including within Orthodox Judaism. In some Sephardic Orthodox communities, young boys wear a tallit even before becoming b'nei mitzvah. In some communities, it is worn beginning with a boy's bar mitzvah, though the tallit katan is often worn from preschool age. In many Orthodox Ashkenazi Jewish communities, a tallit gadol is worn only after marriage and may be given to a groom as a wedding present or, in the most conservative communities, as part of a dowry.^{[citation needed]}

The Hebrew Bible does not command wearing a prayer shawl. Instead, it presumes that people wore a garment of some type to cover themselves and instructs the Israelites to attach fringes (ציצית tzitzit) to the corners of these in Numbers 15:38, which is repeated in Deuteronomy 22:12: "You shall make tassels on the four corners of the garment with which you cover yourself." These passages do not specify tying particular types or numbers of knots in the fringes.

Customs regarding the tying of the tzitzit and the format of the tallit are of Rabbinic origin and, though the Talmud discusses these matters, slightly different traditions have developed in different communities. However the Bible is specific as to the purpose of these tzitzit, stating that "it shall be unto you for a fringe, that ye may look upon it, and remember all the commandments of the LORD, and do them; and that ye go not about after your own heart and your own eyes, after which ye use to go astray; that ye may remember and do all My commandments, and be holy unto your God".

The Encyclopaedia Judaica describes the prayer shawl as "a rectangular mantle that looked like a blanket and was worn by men in ancient times". Also, it "is usually white and made either of wool, cotton, or silk".

Traditionally, a tallit is made of wool or linen, based on an understanding that reference to a "garment" in the Bible in connection with a mitzvah refers to wool and linen garments. Though other materials are sometimes used, the debate has not reached a conclusion, and many, especially among the orthodox, prefer wool, which is accepted by all authorities. There is also debate about mixed wool and linen tallit, since the Bible forbids kelayim (shatnez)—"intertying" wool and linen together, with the two exceptions being the garments of the priests of the Temple and the tzitzit. Concerning tzitzit, chazal (the sages) permit using wool and linen strings in tandem only when genuine tekhelet (see below) is available, whereas kabbalist sources take it a step further by encouraging its practice.

According to the biblical commandment in Numbers 15:38, a "tekhelet" thread is included in the tzitzit. (The colour of the tekhelet dye varies from blue to purple and red, although blue is the colour specifically associated with it in Judaism.) However, for many centuries since the Jewish diaspora, tzitzit have been worn without a tekhelet fringe, though there has been something of a comeback in the last hundred years.