Cerebellar GABAergic projection neurons and interneurons originate from the ventricular neuroepithelium of the cerebellar primordium. However, while projection neurons are born within this germinal layer, interneurons derive from progenitors that delaminate into the prospective white matter. In spite of this common origin, the two main classes of GABAergic neurons are generated according to distinct strategies. Projection neurons are committed to their fate at early ontogenetic stages and acquire their mature phenotypes through cell-autonomous mechanisms. On the contrary, the different categories of cerebellar interneurons derive from a single pool of multipotent progenitors, whose fate choices, production rates and differentiation schedules are strongly influenced by environmental cues.