The main objective of this paper is to discuss the experimental and theoretical approaches developed by different researchers in order to understand and to evaluate the soil geosynthetic interaction under different loading conditions. In the paper, the soil-geosynthetic interaction in pullout, direct shear, and inclined plane tests under both static and cyclic loading is analyzed based on the different theoretical and experimental results carried out by the authors and also available in literature. For each type of test, the factors affecting test results and soil-geosynthetic interface behavior, the theoretical model developed to predict the interface resistance and mobilized friction, and the relevance of the interface parameters obtained through the different tests in the design and performance of geosynthetic reinforced earth structures are discussed in detail.