Karaite Judaism () or Karaism (, sometimes spelt Karaitism (; Hebrew: יהדות קראית Yahadut Qara'it); also spelt Qaraite Judaism, Qaraism or Qaraitism) is a Jewish religious movement characterized by the recognition of the written Tanakh alone as its supreme authority in halakha (Jewish religious law) and theology. Karaites believe that all of the divine commandments which were handed down to Moses by God were recorded in the written Torah without any additional Oral Law or explanation. Unlike mainstream Rabbinic Judaism, which considers the Oral Torah, codified in the Talmud and subsequent works, to be authoritative interpretations of the Torah, Karaite Jews do not believe that the written collections of the oral tradition in the Midrash or the Talmud are binding.

When they read the Torah, Karaites strive to adhere to the plain or most obvious meaning (peshat) of the text; this is not necessarily the literal meaning of the text, instead, it is the meaning of the text that would have been naturally understood by the ancient Hebrews when the books of the Torah were first written - without the use of the Oral Torah. By contrast, Rabbinic Judaism relies on the legal rulings of the Sanhedrin as they are codified in the Midrash, Talmud, and other sources to indicate the authentic meaning of the Torah. Karaite Judaism holds every interpretation of the Torah to the same scrutiny regardless of its source, and teaches that it is the personal responsibility of every individual Jew to study the Torah, and ultimately decide personally its correct meaning. Karaites may consider arguments made in the Talmud and other works without exalting them above other viewpoints.

According to Mordecai ben Nissan, the ancestors of the Karaites were a group called Benei Ṣedeq during the Second Temple period. Historians have argued over whether Karaism has a direct connection to the Sadducees dating back to the end of the Second Temple period (70 CE) or whether Karaism represents a novel emergence of similar views. Karaites have always maintained that while there are some similarities to the Sadducees due to the rejection of rabbinical authority and the Oral Law, there are major differences.

According to Rabbi Abraham ibn Daud, in his Sefer ha-Qabbalah, the Karaite movement crystallized in Baghdad in the Gaonic period (circa 7th–9th centuries) under the Abbasid Caliphate in what is now Iraq. This is the view universally accepted among Rabbinic Jews. However, some Arab scholars claim that Karaites were already living in Egypt in the first half of the seventh century, based on a legal document that the Karaite community in Egypt had in its possession until the end of the 19th century, in which the first Islamic governor ordered the leaders of the Rabbinite community against interfering with Karaite practices or the way they celebrate their holidays. It was said to have been stamped by the palm of Amr ibn al-ʿĀṣ as-Sahmī, the first Islamic governor of Egypt (d. 664), and was reportedly dated 20 AH (641 CE).

At one time, Karaites made up a significant proportion of the Jewish population. In the 21st century, some 30,000–50,000 are thought to reside in Israel, with smaller communities in Turkey, Europe and the United States. Another estimate holds that, of the 50,000 worldwide, more than 40,000 descend from those who made aliyah from Egypt and Iraq to Israel. The largest Karaite community today resides in the Israeli city of Ashdod.