Tzimtzum (Hebrew צמצום ṣimṣūm "contraction" or "constriction") is a term used in the Lurianic Kabbalah teaching of Isaac Luria, explaining his concept that God began the process of creation by "contracting" his infinite light in order to allow for a "conceptual space" in which a finite and seemingly independent world could exist. This contraction, forming an "empty space" (חלל הפנוי) in which creation could begin, is known as the Tzimtzum.

Because the Tzimtzum results in the conceptual "space" in which the physical universe and free will can exist, God is often referred to as "Ha-Makom" (המקום lit. "the place", "the omnipresent") in Rabbinic literature. Relatedly, olam—the Hebrew word for "world" or universe—is derived from the root word עלם meaning "concealment". This etymology is complementary with the concept of Tzimtzum, in that the physical universe conceals the spiritual nature of creation.

Isaac Luria introduced three central themes into kabbalistic thought, Tzimtzum, Shevirat HaKelim (the shattering of the vessels), and Tikkun (repair). These three are a group of interrelated, and continuing, processes. Tzimzum describes the first step in the process by which God began the process of creation by withdrawing his own essence from an area, creating an area in which creation could begin. Shevirat HaKelim describes how, after the Tzimtzum, God created the vessels (HaKelim) in the empty space, and how when God began to pour his Light into the vessels they were not strong enough to hold the power of God's Light and shattered (Shevirat). The third step, Tikkun, is the process of gathering together, and raising, the sparks of God's Light that were carried down with the shards of the shattered vessels.