Puerta de Hierro (Spanish for Iron Gate) is a monument of the second half of the 18th century, located in the northwest of Madrid, Spain, in the district of Moncloa near the Monte de El Pardo.

It occupies a landscaped traffic island, defined by several branches of the highway A-6 and M-30, an enclave which is difficult to access.

It was erected here because this was the ceremonial entrance to the Royal Park of El Pardo, a hunting area historically reserved to the Spanish monarchy and, at present, it is protected through the Regional Park of the Cuenca Alta del Manzanares [es].

The Argentine president Juan Domingo Perón had a villa there during his Spanish exile.

The area is also known for its world famous country club, Real Club de la Puerta de Hierro.