Micro-/nano-structured biomaterials with tuneable architectures and functionalities have found promising applications and facile fabrication strategies play a key role in controlling the morphological aspects. Here, green surfactants, rhamnolipid and surfactin were used to cap and stabilize zinc oxide at basic pH and compared with that synthesized using a synthetic surfactant, i.e., sodium dodecyl sulphate. The surfactant@ZnO was characterized by XRD, TGA, FTIR, SEM-EDS, TEM, XPS, AFM, DLS, UV–Vis and PL tests. The XRD, FTIR and XPS data show the successful formation of surfactant@ZnO. The SEM and TEM studies have revealed the various morphologies of ZnO. The UV–Vis and PL studies established the optical characteristics of the surfactant@ZnO. The AFM and DLS were used to examine the effect of surfactant on the size and stability of the ZnO micro- and nanostructures. It is found that the green surfactant@ZnO are more effective in controlling the crystallite size to as low as 13 nm. It is observed that the bio-surfactants meet the bare minimum criteria of a green template to control the size, morphology and optical properties of zinc oxide through a characteristic self-assembly route, essential for the rational development of nano-biomaterials which are anticipated to be widely used in industrial applications.