The Royal Gate of the Botanical Garden was designed as a triumphal arch in the Neoclassical style by senior architect Francesco Sabatini, by order of King Charles III, in the late eighteenth century. The King intended to move the Botanical Garden designed by his half-brother, King Ferdinand VI, from Soto de Migas Calientes, by the river Manzanares, to its current location, south of the Royal Site of El Buen Retiro, as part of the renovation project for Paseo del Prado.

Built in granite and wrought iron, the Royal Gate is a three-archway gate, featuring a central archway and two side entryways with lintels. The central archway is flanked by two Doric columns resting on a plinth, whose capitals support an entablature with frieze, cornice and pediment – the classical design. A metal gate was added later to the central archway. The side entryways feature gates similar to the ones used to enclose the garden.

In 1976, during the restoration of the Botanical Garden, two domed, round stone guard posts were added.

Today, the Royal Gate is always closed – an ornamental feature and landmark facing Paseo del Prado.