The Jewish festival of Passover (Hebrew, and Yiddish: פֶּסַח, Tiberian: pɛsaħ, Israeli: Pesach, Pesah, Pesakh) is celebrated on the 14th day of the month called Nisan ( ; , ), first month of the Jewish year. It immediately precedes the Festival of the Unleavened Bread (חַג הַמַּצּוֹת, ħaɣ ham:asʕ:oθ, Chag Hamatzot/s), a Jewish holiday which begins on the 15th day of Nisan ( , , ) and is celebrated in the northern spring season. In 2008, it arrives at nightfall on April 19.

Passover commemorates the Exodus, the liberation of the Israelites from Egyptian slavery. As described in the Book of Exodus, Passover marks the "birth" of the Children of Israel who become the Jewish nation, as the Jews' ancestors were freed from being slaves of Pharaoh and allowed to become followers of God instead.

The two names for the holiday are a coalescence of two related celebrations. The name Passover (Pesakh, meaning "skipping" or passing over) derives from the night of the Tenth Plague, when the Angel of Death saw the blood of the Passover lamb on the doorposts of the houses of Israel and "skipped over" them and did not kill their firstborn. The meal of the Passover Seder commemorates this event. The name Feast of Unleavened Bread (Khag Ha'Matsot) refers to the weeklong period when leaven has been removed, and unleavened bread or matsa ("flatbread") is eaten.

Together with Sukkot ("Tabernacles") and Shavuot ("Pentecost"), Passover is one of the three pilgrim festivals (Shloshet Ha'Regalim) during which the entire Jewish populace made a pilgrimage to Jerusalem, at the time when the Temple in Jerusalem was standing.

In Israel, Passover is a 7-day holiday, with the first and last days celebrated as a full festival (involving abstention from work, special prayer services and holiday meals). In the Jewish diaspora outside Israel, the holiday is traditionally celebrated for 8 days (although some Reform Jews celebrate for 7 days), with the first two days and last two days celebrated as full festivals. The intervening days are known as Chol HaMoed ("festival weekdays").

The primary symbol of Passover is the matzo, a flat, unleavened "bread" which recalls the hurriedly-baked bread that the Israelites ate after their hasty departure from Egypt. According to Halakha, matzo may be made from flour derived from five types of grain: wheat, barley, spelt, oats and rye. The dough for matzo is made when flour is added to water only, which has not been allowed to rise for more than 18-22 minutes prior to baking.

Many Jews observe the positive Torah commandment of eating matzo on the first night of Passover at the Passover Seder, as well as the Torah prohibition against eating or owning Chametz which includes any leavened products — such as bread, cake, cookies, beer, whiskey or pasta (or anything made from raw dough that had been left alone for more than 18 minutes, as it then begins to ferment) — for the duration of the holiday.