Vayeira, Vayera, or Va-yera (וַיֵּרָא‎—Hebrew for "and He appeared," the first word in the parashah) is the fourth weekly Torah portion (פָּרָשָׁה‎, parashah) in the annual Jewish cycle of Torah reading. It constitutes Genesis 18:1–22:24. The parashah tells the stories of Abraham's three visitors, Abraham's bargaining with God over Sodom and Gomorrah, Lot's two visitors, Lot's bargaining with the Sodomites, Lot's flight, the destruction of Sodom and Gomorrah, how Lot's daughters became pregnant by their father, how Abraham once again passed off his wife Sarah as his sister, the birth of Isaac, the expulsion of Hagar, disputes over wells, and the binding of Isaac (הָעֲקֵידָה‎, the Akedah).

The parashah has the most words (but not the most letters or verses) of any of the weekly Torah portions in the Book of Genesis, and its word-count is second only to Parashat Naso in the entire Torah. It is made up of 7,862 Hebrew letters, 2,085 Hebrew words, 147 verses, and 252 lines in a Torah Scroll (Sefer Torah). (In the Book of Genesis, Parashat Miketz has the most letters, and Parashiyot Noach and Vayishlach have the most verses.)

Jews read it on the fourth Sabbath after Simchat Torah, in October or November. Jews also read parts of the parashah as Torah readings for Rosh Hashanah. Genesis 21 is the Torah reading for the first day of Rosh Hashanah, and Genesis 22 is the Torah reading for the second day of Rosh Hashanah. In Reform Judaism, Genesis 22 is the Torah reading for the one day of Rosh Hashanah.

In traditional Sabbath Torah reading, the parashah is divided into seven readings (עליות‎, aliyot). In the Masoretic Text of the Tanakh (Hebrew Bible), Parashat Vayeira has four "open portion" (פתוחה‎, petuchah) divisions (roughly equivalent to paragraphs, often abbreviated with the Hebrew letter פ‎ (peh)). Parashat Vayeira has two further subdivisions, called "closed portion" (סתומה‎, setumah) divisions (abbreviated with the Hebrew letter ס‎ (samekh)) within the first open portion. The first open portion, petuchah) spans the first five readings. The second open portion coincides with the sixth reading. The third open portion covers the binding of Isaac, which is most of the seventh reading, excluding only the concluding maftir (מפטיר‎) reading. And the fourth open portion coincides with the concluding maftir reading. Closed portion divisions further divide the long fourth reading.

In the first reading, as Abraham was sitting in the entrance of his tent by the terebinths of Mamre in the heat of the day, he looked up and saw God in the form of three men. He ran, bowed to the ground, and welcomed them. Abraham offered to wash their feet and fetch them a morsel of bread, and they assented. Abraham rushed to Sarah's tent to order cakes made from choice flour, ran to select a choice calf for a servant-boy to prepare, set curds and milk and the calf before them, and waited on them under the tree as they ate. (In Genesis 18:9, there are dots above the letters א‎‎, ל‎, and ו‎‎ in "They said to him.") One of the visitors told Abraham that he would return the next year, and Sarah would have a son, but Sarah laughed to herself at the prospect, with Abraham so old. God then asked Abraham why Sarah had laughed at bearing a child at her age, noting that nothing was too wondrous for God. The first reading ends here.

In the second reading, frightened, Sarah denied laughing, but God insisted that she had. The men set out toward Sodom, and Abraham walked with them to see them off. God considered whether to confide in Abraham what God was about to do, since God had singled out Abraham to become a great nation and instruct his posterity to keep God's way by doing what was just and right. God told Abraham that the outrage and sin of Sodom and Gomorrah was so great that God was going to see whether they had acted according to the outcry that had reached God. The men went on to Sodom, while Abraham remained standing before God. Abraham pressed God whether God would sweep away the innocent along with the guilty, asking successively if there were 50, or 45, or 40, or 30, or 20, or 10 innocent people in Sodom, would God not spare the city for the sake of the innocent ones, and each time God agreed to do so. When God had finished speaking to Abraham, God departed, and Abraham returned to his place. The second reading ends here with the end of chapter 18.

In the third reading, as Lot was sitting at the gate of Sodom in the evening, the two angels arrived, and Lot greeted them and bowed low to the ground. Lot invited the angels to spend the night at his house and bathe their feet, but they said that they would spend the night in the square. Lot urged them strongly, so they went to his house, and he prepared a feast for them and baked unleavened bread, and they ate. Before they had retired for the night, all the men of Sodom gathered about the house shouting to Lot to bring his visitors out so that they might be intimate with them. Lot went outside the entrance, shutting the door behind him, and begged the men of Sodom not commit such a wrong. Lot offered the men his two virgin daughters, if they would not do anything to his guests, but they disparaged Lot as one who had come as an alien and now sought to rule them, and they pressed threateningly against him. But the visitors stretched out their hands and pulled Lot back into the house and shut the door and struck the people with blindness so that they were unable to find the door. The visitors directed Lot to bring what family he had out of the city, for they were about to destroy the place, because the outcry against its inhabitants had become so great. So Lot told his sons-in-law that they needed to get out of the place because God was about to destroy it, but Lot's sons-in-law thought that he was joking. As dawn broke, the angels urged Lot to flee with his wife and two remaining daughters, but still he delayed. So out of God's mercy, the men seized Lot, his wife, and daughters and brought them out of the city, telling them to flee for their lives and not to stop or look back anywhere in the plain. But Lot asked them whether he might flee to a little village nearby. The third reading ends here.

In the long fourth reading, the angel replied that he would grant Lot this favor too, and spare that town. The angel urged Lot to hurry there, for the angel could not do anything until he arrived there, and thus the town came to be called Zoar. As the sun rose and Lot entered Zoar, God rained sulfurous fire from heaven on Sodom and Gomorrah and annihilated the entire plain. Lot's wife looked back and turned into a pillar of salt. The next morning, Abraham hurried to the place where he had stood before God and looked down toward Sodom and Gomorrah and saw the smoke rising like at a kiln. Lot was afraid to dwell in Zoar, so he settled in a cave in the hill country with his two daughters. The older daughter told the younger that their father was old, and there was not a man on earth with whom to have children, so she proposed that they get Lot drunk and have sex with him so that they might maintain life through their father. That night they made their father drink wine, and the older one lay with her father without his being aware. And the next day the older one persuaded the younger to do the same. The two daughters thus had children by their father, the older one bore a son named Moab who became the father of the Moabites, and the younger bore a son named Ben-ammi who became the father of the Ammonites. A closed portion ends here with the end of chapter 19.