This paper reports the results of the investigation on the effects of restrained dilatancy to the pull-out resistance of geogrid strip reinforcement embedded in dense granular soil. The pull-out resistance has been conceptualized to comprise a combined two-dimensional (2-D) and three-dimensional (3-D) interaction resistance. The 2-D interaction resistance, which is the classical soil-reinforcement interface friction, is generated over the middle section while the 3-D interaction resistance is generated at both edges of the strip as a consequence of restrained soil dilatancy. The effect of restrained dilatancy would enhance or reduce the pull-out resistance depending on the corresponding potential increase or decrease in dilatancy (i.e., positive or negative dilatancy) during the process of shearing.