Rammed earth is a traditional construction technique widely used all over the world, and which is currently experiencing a resurgence of attention as an eco-friendly building solution. Nevertheless, the general absence of national and international standards based on the structural comprehension of such constructions poses a challenge for architects and builders looking to incorporate this technique into modern building projects. In this context, the present chapter develops a thorough analysis of the state-of-the-art of the knowledge regarding the mechanical and physical properties of rammed earth, modern testing techniques applied to this traditional material and main results, values of consensus, and uncertainties. However, the mechanical properties of unstabilized rammed earth are sometimes not enough to meet the requirements of existing building codes, so stabilization and reinforcement techniques are applied to enhance its mechanical behavior. The second part of the chapter focuses, therefore, on the stabilizing and reinforcing techniques for rammed earth.