Proteins in a weakly aligned state restore the anisotropic nuclear spin interactions for dipoles and chemical shifts, which vanish in rapidly tumbling molecules in an isotropic solution. The partially restored anisotropic nuclear spin interactions, also known as ‘residual anisotropic spin interactions’, observed in a protein offer extra structural information to improve its spatial structure and better understand its structural dynamics over a wider time range than nuclear spin relaxations. The successful utilization of residual anisotropic nuclear spin interactions relies on properly aligning a protein to a degree that balances sensitivity and the magnitude of residual anisotropy. Various types of aligning media are devised to gain residual anisotropy for proteins. The integration of residual anisotropic interactions with the structural data from other methods enabled the investigation of a large amplitude conformational change in a protein, as seen in domain rearrangement. These methods include small-angle X-ray scattering (SAXS), paramagnetic relaxation enhancement (PRE), and pseudo-contact shifts (PCS). Conventional NMR techniques, which rely on short-range structural information from NOEs and scalar nuclear spin couplings, have failed to elucidate such conformational changes of large magnitudes. This chapter covers the residual anisotropy in solution NMR, from the basic theory of residual anisotropic nuclear spin interactions to their application in analyzing protein structure and dynamics.