Tishrei () or Tishri (; Hebrew: תִּשְׁרֵי‎ tīšrē or תִּשְׁרִי‎ tīšrī; from Akkadian tašrītu "beginning", from šurrû "to begin") is the first month of the civil year (which starts on 1 Tishrei) and the seventh month of the ecclesiastical year (which starts on 1 Nisan) in the Hebrew calendar. The name of the month is Babylonian. It is a month of 30 days. Tishrei usually occurs in September–October on the Gregorian calendar.

In the Hebrew Bible the month is called Ethanim (Hebrew: אֵתָנִים – 1 Kings 8:2), or simply the seventh month. In the Babylonian calendar the month is known as Araḫ Tišritum, "Month of Beginning" (of the second half-year).

Edwin R. Thiele has concluded, in The Mysterious Numbers of the Hebrew Kings, that the ancient Kingdom of Judah counted years using the civil year starting in Tishrei, while the Kingdom of Israel counted years using the ecclesiastical new year starting in Nisan. Tishrei is the month used for the counting of the epoch year – i.e., the count of the year is incremented on 1 Tishrei.