The metal-insulator transition in correlated materials is usually coupled to a symmetry-lowering structural phase transition. This coupling not only complicates the understanding of the basic mechanism of this phenomenon but also limits the speed and endurance of prospective electronic devices. Here, we design and demonstrate an isostructural, purely electronically-driven metal-insulator transition in epitaxial heterostructures of an archetypal correlated material vanadium dioxide. A combination of thin-film synthesis, structural and electrical characterizations, and theoretical modeling reveals that an interface interaction suppresses the electronic correlations without changing the crystal structure in this otherwise correlated insulator. It stabilizes a non-equilibrium metallic phase, and leads to an isostructural metal-insulator transition. This discovery will provide insights into correlated phase transitions and may aid the design of device functionalities.