The members of the CIP/KIP family of cyclin‐dependent kinase (CDK) inhibitory proteins (CKIs), including p57^KIP2, p27^KIP1, and p21^CIP1, block the progression of the cell cycle by binding and inhibiting cyclin/CDK complexes of the G1 phase. In addition to this well‐characterized function, p57^KIP2 and p27^KIP1 have been shown to participate in an increasing number of other important cellular processes including cell fate and differentiation, cell motility and migration, and cell death/survival, both in peripheral and central nervous systems. Increasing evidence over the past few years has characterized the functions of the newest CIP/KIP member p57^KIP2 in orchestrating cell proliferation, differentiation, and migration during neurogenesis. Here, we focus our discussion on the multiple roles played by p57^KIP2 during cortical development, making comparisons to p27^KIP1 as well as the INK4 family of CKIs. © 2011 Wiley Periodicals, Inc. Develop Neurobiol 72: 821–842, 2012