The emerging complexity of plant endocytic systems puts it on a par with their animal counterparts, reflecting an essential role in signal transduction. The endocytic machinery regulates the space and the time of signal transduction and processing in the cell. Plants possess numerous cell surface receptor-like kinases (RLKs) (more than 600 members in Arabidopsis thaliana and 1100 in rice), a trend attributed to their indeterminate mode of growth, the absence of cell migration, and the need for adaptation towards the environment. Thus, plants would require a robust and highly plastic endocytic system in order to integrate multiple signaling cues from neighboring cells as well as the environment. Although a comprehensive understanding of how plant endocytosis impacts signaling pathways is still lacking, experimental evidence suggests that both plant and animal endosomal systems extensively control signaling.