Supramolecular polymeric nanotubes based on the self-assembling cyclic peptide-polymer conjugates are a promising class of materials, showing great potential in various biological applications. Herein, we present a novel strategy to promote nanotube assembly through effectively shielding the cyclic peptides from water, via the introduction of varying hydrophobic groups. As determined by a combination of SANS, TEM, and SLS, hydrophobic interactions, π-π stacking, and multiple hydrogen bonding interactions cooperate in the self-assembly of the cyclic peptide-polymer conjugates, allowing for the construction of supramolecular nanotubes that are longer than expected in water. This approach offers an effective pathway toward the design of organic nanotubes of hundreds of nanometers in water.