Self-assembled surfactant aggregates show a large variety in shapes and sizes. Although in some cases the shape can be predicted using the postulates of Israelachvili, what exactly governs the size of the aggregates is not fully understood. It is obvious that the size of well defined self-assembled objects is determined by a fine balance between attractive and repulsive forces. Understanding these forces may lead to control over the dimensions of the aggregates. We present a surfactant molecule (1), in which a bis-ureido group is incorporated in its hydrocarbon chain. Due to strong hydrogen bonds in the length direction, 1 forms well-defined highly ordered ribbon-like aggregates in water. The aspect ratios of these ribbons can be varied between 2.5 to >50 in a controlled manner, using only temperature and concentration. The H-bonds are mainly influenced by temperature and control the length, whereas the width can be controlled by changing concentration.