Silicon nitride ceramics are known for their good mechanical properties and wear resistance. This is the reason why they are used in bearings, for example. In this work, the sliding behavior of Si3N4 ceramics with different microstructures and compositions was investigated. Several promising water and glycol based tribosystems containing Si3N4 materials with different microstructures and exhibiting superlubricity (i.e., coefficient of friction below 0.01) were identified at the model level (ball on 3 plates) and by sliding bearing tests. The surfaces before and after the sliding tests were investigated to identify topographical and tribochemical modifications at the surfaces that are related to macroscopic superlubricity. Based on these results, various mechanisms for the superlubricity of silicon nitride materials are discussed.