Graphene quantum dots (GQDs) have attracted tremendous attention in recent years. In this review, the recent developments are summarized in the synthesis, edge functionalization, and cyctotoxicity of GQDs, followed by presenting a focused overview on their current applications for in vitro fluorescence imaging in cells and tissues as well as in vivo macroscopic and microscopic imaging in animals. Challenges and opportunities in the development of GQDs for bioimaging are also discussed.