Intrinsically disordered proteins (IDPs) yield solutions with tunable phase transition behavior and have been widely applied in designing stimuli-responsive materials. Understanding interactions between amino acid residues of the IDP sequence is critical to designing new IDP-based materials with selective phase behavior, assembly, and mechanical properties. The lack of defined structure for this class of proteins complicates accurate prediction of their molecular-scale behavior. In this review, recent progress is presented in the development and application of simulation methods to describe the behavior of IDPs. Results for elastin-like polypeptides (ELPs) and resilin-like polypeptides (RLPs) are highlighted, focusing on studies that compare simulation results with experimental findings.