Peptoids are a versatile family of oligomeric synthetic molecules that can be customized for many applications. The submonomer solid-phase synthesis of peptoids allows for quick and inexpensive manufacturing and the selection of side chains is nearly limitless. In addition, peptoids that include chiral, aromatic side chains form stable helical secondary structure that leads to the potential for the formation of supramolecular assemblies. The effects of water solubility, helical content, charge placement, and side chain bulk on microsphere formation were studied for seven peptoid sequences. We found that secondary structure and partial water solubility were essential for microsphere formation. In addition, charge placement and side chain bulk affect both the ability to form microspheres and the diameter of the microspheres.