The Arabidopsis gynoecium consists of two congenitally fused carpels that, at maturity, form a bilocular chamber protecting the ovules and placentae produced by the meristematic regions of the carpel margins. This meristematic region also gives rise to a style capped with stigmatic papillae at the apical end of the developing gynoecia and a transmitting tract that connects the stigma to the ovule-bearing chambers. Most data point towards a common evolutionary origin of leaves and carpels and suggest that leaves can be transformed to carpels by expressing only a few carpel identity genes. In this review, we have therefore approached the carpels from the leaf-like organ hidden within by stressing the parallels between leaf and carpel development. Many of the genes with a role in leaf development were first identified by the effect their mutations cause in carpel development, suggesting that the regulatory networks may be more robust in leaves than in the more complex and evolutionary younger carpels. Similar genetic networks ensure the maintenance of adaxial–abaxial, proximal–distal and medial–lateral dichotomies in leaves and carpels. Data have emerged showing that crosstalk and redundancies are characteristics of these pathways, as well as a general interplay of hormonal balances, with auxin as a major morphogen.