The Passover Seder (Hebrew: סֵדֶר, seðɛɾ, "order", "arrangement") is a Jewish ritual feast held on the first night of the Jewish holiday of Passover (the 15th day of Hebrew month of Nisan). Outside of Israel, the Seder is held twice, on the first and second nights of Passover (the 15th and 16th days of Nisan). According to the Gregorian calendar, the holiday usually comes out in April. Families gather around the table on the night of Passover to read the Haggadah, the story of the Israelite exodus from Egypt. Seder customs include drinking of four cups of wine, eating matza and partaking of symbolic foods placed on the Passover Seder Plate. The Seder is a family ritual, although communal Seders are also organized by synagogues, schools and community centers. These Seders are usually open to the general public. With the Haggadah serving as a guide, the Seder is performed in much the same way all over the world.

The Seder is integral to Jewish faith and identity. If not for the Exodus, as explained in the Haggadah, the Jewish people would still be slaves in Egypt. Therefore the Seder is an occasion for praise and thanksgiving. Often the Seder goes on until late at night, with the participants reading the Haggadah, studying the meaning of various passages, and singing special Passover songs.

While many Jewish holidays revolve around the synagogue, the Seder is conducted in the family home. It is customary to invite guests, especially strangers and the needy. The Seder as family-based ritual is derived from a verse in the Bible: Vehigadta levincha' bayom hahu leymor ba'avur zeh asah Adonay li betzeysi miMitzrayim - "And you shall tell it to your son on that day, saying, 'Because of this God did for me when He took me out of Egypt'" (Exodus 13:8). The words and rituals of the Seder are a primary vehicle for the transmission of the Jewish faith from parent to child, and from one generation to the next.

Attending a Seder and eating matza on Passover is a widespread custom in the Jewish community, even among those who are not religiously observant.