Current‐induced control of magnetization in ferromagnets using spin–orbit torque (SOT) has drawn attention as a new mechanism for fast and energy efficient magnetic memory devices. Energy‐efficient spintronic devices require a spin‐current source with a large SOT efficiency (ξ) and electrical conductivity (σ), and an efficient spin injection across a transparent interface. Herein, single crystals of the van der Waals (vdW) topological semimetal WTe2 and vdW ferromagnet Fe3GeTe2 are used to satisfy the requirements in their all‐vdW‐heterostructure with an atomically sharp interface. The results exhibit values of ξ ≈ 4.6 and σ ≈ 2.25 × 105 Ω‐1 m‐1 for WTe2. Moreover, the significantly reduced switching current density of 3.90 × 106 A cm−2 at 150 K is obtained, which is an order of magnitude smaller than those of conventional heavy‐metal/ferromagnet thin films. These findings highlight that engineering vdW‐type topological materials and magnets offers a promising route to energy‐efficient magnetization control in SOT‐based spintronics. All‐van der Waals (vdW) heterostructure with an atomically sharp interface based on topological semimetal shows spin–orbit torque (SOT)‐driven magnetization switching. These findings highlight that engineering vdW‐type topological materials and magnets offers a promising route to energy‐efficient magnetization control in SOT‐based spintronics.