GABAergic interneurons powerfully control the function of cortical networks. In addition, they strongly regulate cortical development by modulating several cellular processes such as neuronal proliferation, migration, differentiation and connectivity. Not surprisingly, aberrant development of GABAergic circuits has been implicated in many neurodevelopmental disorders including schizophrenia, autism and Tourette’s syndrome. Unfortunately, efforts directed towards the comprehension of the mechanisms regulating GABAergic circuits formation and function have been impaired by the strikingly heterogeneity, both at the morphological and functional level, of GABAergic interneurons. Recent technical advances, including the improvement of interneurons-specific labelling techniques, have started to reveal the basic principles underlying this process. This review summarizes recent findings on the mechanisms underlying the construction of GABAergic circuits in the cortex, with a particular focus on potential implications for brain diseases with neurodevelopmental origin.