Cappella d'Oro, Renaissance chapel in Gaeta, Italy.

Cappella d'Oro, also called the chapel of the Immaculate Conception, is a single-nave chapel inside the sanctuary of the Santissima Annunziata in Gaeta, entered from Via Annunziata through a marble Baroque portal by Dionisio Lazzari. Its lowered barrel vault carries an octagonal wooden coffered ceiling finished in gold leaf, and the walls are lined with a wooden boiserie below the painted cycle.

The chapel was built in the 14th century. In the first half of the 16th century it received its wooden ceiling and the signed and dated 1531 painting cycle by Giovanni Filippo Criscuolo. The Baroque marble portal by Dionisio Lazzari was added in the following century.

The chapel is also called Cappella d'Oro for its wooden ceiling with pure gold leaf finishing. Its name recalls the dedication to the Immaculate Conception, and a plaque left of the portal records that Pius IX often came here to pray during his exile in Gaeta.

The chapel opens onto Via Annunziata at number 21, inside the sanctuary of the Santissima Annunziata, and is entered through Dionisio Lazzari's marble portal. The single nave has no apse and is small enough to view in a short visit; the only daylight comes from the window in the pediment above the entrance.

A marble plaque left of the Baroque portal records that Pius IX, during his exile in Gaeta, often came to pray in this chapel. According to tradition, it was here that he received the inspiration for the dogma of the Immaculate Conception, proclaimed in 1854.