Shema Yisrael (Shema Israel or Sh'ma Yisrael; Hebrew: שְׁמַע יִשְׂרָאֵל Šəmaʿ Yīsrāʾēl, "Hear, O Israel") is a Jewish prayer (known as the Shema) that serves as a centerpiece of the morning and evening Jewish prayer services. Its first verse encapsulates the monotheistic essence of Judaism: "Hear, O Israel: YHWH is our God, YHWH is one" (Hebrew: שְׁמַע יִשְׂרָאֵל יְהוָה אֱלֹהֵינוּ יְהוָה אֶחָֽד׃), found in Deuteronomy 6:4.

The first part can be translated as either "The LORD our God" or "The LORD is our God", and the second part as either "the LORD is one" or as "the one LORD" (in the sense of "the LORD alone"), since Hebrew does not normally use a copula in the present tense, so translators must decide by inference whether one is appropriate in English. The word used for "the LORD" is the tetragrammaton YHWH.

Observant Jews consider the Shema to be the most important part of the prayer service in Judaism, and its twice-daily recitation as a mitzvah (religious commandment). Also, it is traditional for Jews to say the Shema as their last words, and for parents to teach their children to say it before they go to sleep at night.

The term Shema is used by extension to refer to the whole part of the daily prayers that commences with Shema Yisrael and comprises Deuteronomy 6:4–9, 11:13–21, and Numbers 15:37–41. These sections of the Torah are read in the weekly Torah portions Va'etchanan, Eikev, and Shlach, respectively.