Recent materials research based on fluorescent nanocelluloses (NCs) used in the field of sensing and bioimaging is reviewed. Many designed morphologies have been reported, such as nanoparticles, fibers, nanopapers, hydrogels and aerogels, that have been produced by physical or chemical methods. In the field of sensing and bioimaging, these studies have involved, but not been limited to, special optical properties including fluorescence, long-lived luminescence, polarized light, and/or aggregation-induced emission. The fluorescence sensing platforms can be categorized according to stimuli such as pH and temperature, as well as the presence of toxic compounds, and anions and metal cations. In addition, NCs exhibit unique low toxicity, good biocompatibility, biodegradability and cell membrane penetration, and can be modified into fluorescent nanoprobes for in vivo imaging and tracing. As an excellent platform for fluorescent sensing and bioimaging, NCs are bound to be increasingly studied and widely applied in the field of production and life sciences.