The Hedgehog (Hh) pathway is a signaling cascade that directs patterning in most animals and is crucial for proper development. At the molecular level, Hh ligands drive cell proliferation in some cell types while causing others to undergo differentiation. Hh signaling is most active during embryogenesis, and aberrant reactivation of the pathway in adult tissue can lead to the development of cancer. A comprehensive understanding of Hh signaling during development will undoubtedly shed light into the mechanism of Hh in cancer progression and identify potential targets for therapeutic intervention.