The interface behavior between soil and geosynthetics plays a key role in reinforced soil structures. The soil-geosynthetic interface resistance, usually obtained by pullout or direct shear tests, is an essential parameter for design analysis, whose effect of particle shape and size, soil moisture content and normal stress are very important factors of influence. In the case of sandy soils, dilatancy and its dependency on the type of geosynthetics are the factors that can influence the resistance behavior. Also, under partially saturated conditions, soil suction and dilatancy are strictly related, although not fully understood. This study is based on pullout tests performed with two different types of geosynthetics (a geogrid and a woven geotextile) embedded in a well-graded sand compacted at different moisture conditions. A small-scale pullout apparatus was fully instrumented to monitor internal displacements, induced vertical earth pressure, soil suction and vertical displacements during pullout. Results showed that the pullout dilatancy at the sand-geogrid interfaces is significant and greater than the soil itself. On the other hand, geotextile showed a compression effect on all developed interfaces. It was found that the high values of dilatancy of interfaces with geogrid were associated to lower values of soil suction. It could be concluded that capillarity effects and dilatancy are significant in the soil-geosynthetic interface resistance.