Nanoscale amorphous olivine (a-olivine) intracrystalline layers, which can form in olivine polycrystals under high stress, has the potential to influence the mechanical properties of the rock in the vicinity of the brittle–ductile transition. It is therefore essential to determine the mechanical properties, in particular the strength, of these a-olivine films. To this end, we investigate the tensile deformation and fracture of a-olivine thin films deposited on a polymer substrate. Typical brittle fracture in the form of numerous long, straight cracks that are parallel to each other is observed during a tensile test. Using in situ measurements of electrical resistance, the critical strain required for the generation of the first cracks was measured at 0.8 %. A combination of in situ straining with optical microscopy and subsequent digital image correlation enables direct measurements of local strains within the unfractured film regions. It is demonstrated that a-olivine can withstand tensile strains of at least 2 %, which leads to an estimated intrinsic strength of 1.8 GPa. The results presented should contribute to a more comprehensive understanding of the mechanical behavior of olivine-rich rocks affected by grain boundary amorphization.