Glycosaminoglycans (GAGs) are a class of linear, sulfated polysaccharides. These extracellular polysaccharides interact with a range of protein partners and are active in controlling important biological phenomena, including reproduction, cell growth and differentiation, blood coagulation and immune system activation. As a result, interests in developing methods to control specific protein-GAG interactions are high. However, little high-resolution structural information on protein-GAG interactions is available, and predicting a protein's specificity for different GAG motifs remains challenging. Solution NMR has played crucial roles in analyzing specificity and dynamics of protein-GAG interactions. It is instrumental in determining GAG-binding sites of proteins and elucidating GAG-induced changes in protein dynamics. NMR's adaptability to GAG size and sulfation density means the technique can be used to investigate a large class of protein-GAG interactions even if homogeneous GAG samples are not available. In this chapter we will review some of the popular NMR techniques for studying protein-GAG interactions will be reviewed. Challenges in the study of protein-GAG systems and new techniques that may help in overcoming these challenges will also be examined.