Micron-sized, spherical SiO2 particles are important in various industrial applications, such as in heterogeneous catalyst preparation. In particular, many of industrially relevant olefin polymerization catalysts are currently prepared using micro-spherical silica as catalyst support. In large-scale catalytic polyolefin production, the quality of the final product, as well as the process efficiency is crucially dependent on overall consistency, quality, and physico-chemical properties of the catalyst. As the catalyst particle experiences various stresses during the polymer particle growth, mechanical properties of catalyst play a key role in its performance in the polymerization process. However, there is currently a lack of experimental mechanical property measurements of micron-sized, spherical SiO2 particles relevant for the polyolefin catalyst production. In this work, compressive properties of commercial porous micro-spherical silicas were studied using a quasi-static micro-compression method. The method includes compressing single, micron-sized particles in controlled loading conditions. From the measurements, the compressive elastic–plastic properties of these particles can be determined.