Animals are able to move and react in manifold ways to external stimuli. Thus, environmental stimuli need to be detected, information must be processed, and, finally, an output decision must be transmitted to the musculature to get the animal moving. All these processes depend on the nervous system which comprises an intricate neuronal network and many glial cells. Glial cells have an equally important contribution in nervous system function as their neuronal counterpart. Manifold roles are attributed to glia ranging from controlling neuronal cell number and axonal pathfinding to regulation of synapse formation, function, and plasticity. Glial cells metabolically support neurons and contribute to the blood–brain barrier. All of the aforementioned aspects require extensive cell–cell interactions between neurons and glial cells. Not surprisingly, many of these processes are found in all phyla executed by evolutionarily conserved molecules. Here, we review the recent advance in understanding neuron–glia interaction in Drosophila melanogaster to suggest that work in simple model organisms will shed light on the function of mammalian glial cells, too.