Soil ecological knowledge may be key to restoration success in the Anthropocene because ecosystems will continue to degrade as the human population and demand for resources continues to increase. The relevance of such knowledge for restoration success ranges from straightforward to complex, depending on the nature of the disturbance and type of ecosystem. This symposium aims to synthesize how restoration science is increasingly recognizing soil as 1) a medium that can be manipulated to achieve restoration goals, including resilience, 2) an obstacle or threshold that must be overcome to make restoration possible, or 3) a system property that once altered to a particular extent leads to irreversible state transitions. If soil functions as an ecological filter in the community assembly process, to what degree can it be manipulated to promote restored species and beneficial ecosystem functions? When do physical or biological changes to soil resulting from disturbance or invasion impose thresholds that obstruct recovery of ecosystem structure and function? Severely altered systems can represent the lowest probability of restoration success if tipping points have been crossed. How often is this phenomenon perpetuated by irreversible changes to soil? A collection of perspectives from restoration studies in mined, heavily invaded, overgrazed, and former agricultural lands that span desert, grassland, and forest ecosystems will further develop our ability to identify the soil ecological knowledge needed to better guide ecological restoration, elucidate system properties and processes that can help to cross or avoid thresholds that determine outcomes, and predict soil-related tipping points that result in failure. The symposium will highlight the importance of soil ecological knowledge in responsibly allocating effort and resources to restorations with the highest probability of success.