Zeolites are materials that can be produced naturally and/or synthetically with a wide common usage area. There are different types of zeolites according to their usage areas and sizes. Greases are generally classified according to their soap types. Although, it is necessary to add load resistance and wear improving additives to the formulation of most grease products when they are operated under heavy loads in their usage conditions. In this study, the potential of clinoptilolite type zeolites to be applied as solid lubricants was investigated. In order to investigate the effect of particle size on solid lubricant performance of clinoptilolite zeolites, 10 µm, 40 µm, 100 µm and 700 µm sized zeolites were selected and used. The performance characteristics of clinoptilolite type zeolites in lithium soap grease products when used as load resistance and wear improving additives were investigated. In addition, the effect of size on the anti-wear and load resistance performances of clinoptilolite type zeolites in lithium soap greases was investigated and detailed results were reported.