Christianity (Hebrew: נצרות, romanized: Natsrút; Arabic: المسيحية, romanized: al-Masīḥiyya; Imperial Aramaic: ܢܘܨܪܝܐ ܕܐܪܥܐ ܕܝܣܪܐܝܠ) is the third largest religion in Israel, after Judaism and Islam. At the end of 2022, Christians made up 1.9% of the Israeli population, numbering approximately 185,000. 75.8% of the Christians in Israel are Arab Christians. Christians make up 6.9% of the Arab-Israeli population.

Ten Christian churches are formally recognized under Israel's confessional system, for the self-regulation and state recognition of status issues, such as marriage and divorce: the Armenian Apostolic Church, the Armenian Catholic Church, the Chaldean Catholic Church, the Episcopal Church in Jerusalem and the Middle East, the Greek Orthodox Church, the Latin Catholic Church, the Melkite Greek Catholic Church, the Syriac Catholic Church, the Syriac Maronite Church, and the Syriac Orthodox Church. However, the practice of religion is free, with no restrictions on the practice of other denominations. Approximately 300 Christians have converted from Islam according to one 2014 estimate, and most of them are part of the Catholic Church. About 20,000 Israelis practice Messianic Judaism, usually considered a syncretist form of Christianity.

Arab Christians are mostly adherents of the Melkite Greek Catholic Church (60% of Arab Christians in Israel). Some 40% of all Israeli Christians are affiliated with the Melkite Greek Church, and some 30% with the Greek Orthodox Patriarchate of Jerusalem. Smaller numbers are split between the Latin Patriarchate of Jerusalem, with 13% of Christians, as well as an unknown number of Russian Orthodox Christians, about 13,000 Maronites and other Syriac Christians, 3,000 to 5,000 adherents of Armenian churches, a community of around 1,000 Coptic Christians, and small branches of Protestants. The number of Christians in Israel is higher than in the Occupied Palestinian territories.

Christians in Israel are historically bound with neighbouring Lebanese, Syrian, and Palestinian Christians. The cities and communities where most Christians in Israel reside are Haifa, Nazareth, Shefa-Amr, Jish, Mi'ilya, Fassuta and Kafr Yasif. The Christian communities in Israel run numerous schools, colleges, hospitals, clinics, orphanages, homes for the elderly, dormitories, family and youth centers, hotels, and guesthouses. The Christian community in Israel is one of the few growing Christian populations in the Middle East. Israeli Arab Christians generally have higher educational achievements and enjoy higher incomes than their Druze and Muslim counterparts.

Early Christianity is generally reckoned by Church historians to begin with the ministry of Jesus (c. 27–30) and end with the First Council of Nicaea (325). It is typically divided into two periods: the Apostolic Age (c. 30–100, when the first apostles were still alive) and the Ante-Nicene Period (c. 100–325). Driven by a universalist logic, Christianity has been, from its beginnings, a missionary faith with global aspirations. It first spread through the Jewish diaspora along the trade and travel routes followed by merchants, soldiers, and migrating tribes. It achieved critical mass in the years between 150 and 250 when it moved from fewer than 50,000 adherents to over a million. This provided enough adopters for its growth rate to be self-sustaining.

Christianity originated in 1st-century Judea from a sect of apocalyptic Jewish Christians within the realm of Second Temple Judaism. The basic tenets of the Jewish religion during this era were ethical monotheism and the Torah, or the Mosaic Law. In this period, the Second Temple of Jerusalem was still central to Judaism, but synagogues were also established as institutions for prayer and the reading of Jewish sacred texts. The Hebrew Bible developed during the Second Temple Period, as the Jews decided which religious texts were of divine origin; the Masoretic Text, compiled by the Jewish scribes and scholars of the Early Middle Ages, comprises the Hebrew and Aramaic 24 books that they considered authoritative.

The Hellenized Greek-speaking Jews of Alexandria produced a Greek translation of the Hebrew Bible called "the Septuagint", that included books later identified as the Apocrypha, while the Samaritans produced their own edition of the Torah, the Samaritan Pentateuch; according to the Dutch–Israeli biblical scholar and linguist Emanuel Tov, professor of Bible Studies at the Hebrew University of Jerusalem, both of these ancient editions of the Hebrew Bible differ significantly from the medieval Masoretic Text. Currently, all the main non-Protestant (Roman Catholic, Eastern Orthodox, and Oriental Orthodox) Christian denominations accept as canonical the Deuterocanonical books, which were excluded from the modern Hebrew Bible and the Protestant Bible. The Septuagint was influential on early Christianity as it was the Hellenistic Greek translation of the Hebrew Bible primarily used by the 1st-century Christian authors.

The religious, social, and political climate of 1st-century Roman Judea and its neighbouring provinces was extremely diverse and constantly characterized by socio-political turmoil, with numerous Judaic movements that were both religious and political. The ancient Roman–Jewish historian Flavius Josephus described the four most prominent sects within Second Temple Judaism: Pharisees, Sadducees, Essenes, and an unnamed "fourth philosophy", which modern historians recognize to be the Zealots and Sicarii. The 1st century BC and 1st century AD had numerous charismatic religious leaders contributing to what would become the Mishnah of Rabbinic Judaism, including the Jewish sages Yohanan ben Zakkai and Hanina ben Dosa. Jewish messianism, and the Jewish Messiah concept, has its roots in the apocalyptic literature produced between the 2nd century BC and the 1st century BC, promising a future "anointed" leader (messiah or king) from the Davidic line to resurrect the Israelite Kingdom of God, in place of the foreign rulers of the time.