Abstract Here, we demonstrate that introduction of halogen atoms at the tyrosine 10 phenol ring of the DSGYEV sequence derived from the flexible amyloid‐β N‐terminus, promotes its self‐assembly in the solid state. In particular, we report the crystal structures of two halogen‐modified sequences, which we found to be stabilized in the solid state by halogen‐mediated interactions. The structural study is corroborated by Non‐Covalent Interaction (NCI) analysis. Our results prove that selective halogenation of an amino acid enhances the supramolecular organization of otherwise unstructured biologically‐relevant sequences. This method may develop as a general strategy for stabilizing highly polymorphic peptide regions.