An effective technique was developed to make the first ever determination of shear stress between dielectrophoretically assembled single-wall carbon nanotubes (SWNTs) and substrates using a combination of measurements and modeling. The measurements are based on simple NEMS cantilever beams, a nanomanipulator, and a scanning electron microscope (SEM). This paper presents the determined interfacial shear stress between a small bundle of SWNTs and a gold surface with and without a self-assembled monolayer of alkanethiol (2-phenylethanethiol or 2-aminoethanethiol). An average shear stress of 87 MPa based on 6 independent tests was obtained for gold cantilever substrate. For phenylethanethiol substrate, carbon nanotubes slip much easier than on bare gold surface, suggesting a much lower shear stress. While on amimoethanethiol substrate, nanotubes stick to the surface so well that prevents the slip phenomenon occurring.