  We investigate the three-dimensional electronic structure of the seminal
charge-density-wave (CDW) material 2H-NbSe$_2$ by soft x-ray angle-resolved
photoelectron spectroscopy and density-functional theory. Our results reveal
the pronounced 3D character of the electronic structure formed in the
quasi-two-dimensional layered crystal structure. In particular, we find a
strong dispersion along $k_z$ excluding a nesting-driven CDW formation based on
experimental data. The 3D-like band structure of 2H-NbSe$_2$ has strong
implications for the intriguing phase competition of CDW order with
superconductivity.
