In this study, we investigated the low-frequency Raman spectra of six different amyloid fibrils prepared from Aβ 25-35 , amylin 20-29 , and full-length Aβ 1-40 and amylin peptides. We do not observe any obvious low-frequency spectral features in fibrils that explicitly correlate to parallel or antiparallel βsheet structures. However, the spectra do exhibit several characteristic features that can be used to probe the supramolecular structure of amyloid fibrils, such as the packing of side chains and strands within β-sheets. The spectra are dominated by a broad, intense feature that occurs between ∼ 15 -140 cm -1 . The underlying substructure of this feature is apparent in highly ordered fibrils such as those prepared from Aβ 25-35 and amylin 20-29 , which show a resolved triplet set of peaks near ∼ 60 -80 cm -1 , 110 cm -1 , and 140 cm -1 . These peaks derive from inter-strand C--O• • •H-N hydrogen bond stretching and deformation modes that can be used to quantify the ordering and strength of interactions between β-strands. Additionally, the spectra show several peaks between ∼ 200 -420 cm -1 that are sensitive to the interactions of aliphatic side chains between β-sheets in fibrils. This is of significant potential interest to structural biologists, as it is difficult to directly resolve side chain structures in amyloid fibrils using conventional characterization methods such as ssNMR and cryo-EM. Future studies should investigate the theoretical origins of these low-frequency bands in more detail. Potential methods to do this include (quasi-)continuum mechanical modeling of fibrils 113 or plane-wave DFT calculations. Overall, we anticipate that this work lays the foundation for guiding these future studies to investigate in more detail the low-frequency Raman modes of amyloid fibrils and how they report on their supramolecular structural properties. lution and derivations of eqs. 2 and 3. Files containing the Raman spectra of the fibrils.