Biological macromolecules are typically organized according to specific structural patterns that exhibit a degree of long-range order, yet they also display significant intrinsic disorder. Additionally, the ubiquitous presence of water will build interactions with the biological surfaces, diffuse around and within the hydration layers surrounding macromolecules. These interactions create the necessary spatial freedom for conformational flexibility, which is essential for biological function. This infers that function is facilitated by a wide range of atomic motions across multiple time and length scales, and neutron spectroscopy (NS) emerges as a powerful experimental technique uniquely suited to probing these complex dynamics. Unlike other spectroscopies, NS captures both the time-resolved motions and the spatial arrangement of atoms, offering a multiscale view of biological systems. While NS has been widely applied to study hydration and dynamics in proteins, its potential in exploring RNA structure and function remains almost unexplored. This chapter introduces the fundamental principles of NS and emphasizes its application to biological questions, with a particular focus on the emerging prospects for studying RNA dynamics and structure.