Biomedical imaging is a powerful tool for the diagnosis and treatment of diseases. Various small molecules, polymers, and nanomaterials have been used as contrast-enhancing imaging agents to achieve multifunctional imaging applications. Among them, peptides and peptide-based materials have been attracted growth interesting due to their excellent biocompatibility and diverse biological functions. This article summarized recent advances in developing peptide-based nanomaterial for bioimaging applications, including fluorescence imaging (FLI), photoacoustic imaging (PAI), magnetic resonance imaging (MRI), positron emission tomography (PET), and X-ray computed tomography (CT). In addition to biomedical imaging, peptides and peptide-based materials with therapeutic functions used for the treatment of disease were also involved. Moreover, the perspective and challenge on the future of peptide nanomaterials for bioimaging were also discussed. We hope such a work would stimulate this fast-developing research area.