Soft nanoparticles with precisely controlled shape and morphologies hold great potential for the preparation of novel materials with tailored chemical and biophysical properties. In this review, we highlight the synthetic approaches and hierarchical strategies to manipulate the shape and morphology of nanostructures assembled from four major building units, namely block copolymers, peptide amphiphiles, proteins and nucleic acid building blocks. Special attention is given to anisotropic, stimuli-responsive nanoparticles that are tuned by assembly conditions. Their tunable nature is of particular significance as it allows the design of smart and dynamic materials. The immediate and potential applications of these shape controlled nanostructures are also summarized together with their limitations.