Sant'Angelo a Segno, Neoclassical church in Naples, Italy

Sant'Angelo a Segno is a deconsecrated church at Via dei Tribunali 45 in Naples, rebuilt in Neoclassical form in 1825 to a design by Luigi Malesci. The pale marble plaque on the entrance door recalls the episode behind the name; after a conservative restoration the building was converted into a small neighbourhood theatre.

The church's origin is debated: some trace it to the 7th century, when Bishop Sant'Agnello of Naples repelled the Lombards with a cross, while others place it around 574 during a repulse of the Saracens. The present Neoclassical building was rebuilt in 1825 to a design by Luigi Malesci. It was closed for worship in the 1960s, and its artworks were moved to the Museo di Capodimonte.

The name "a Segno" refers to a nail driven into the church threshold to mark the limit of the Lombard advance, which some sources instead attribute to the Saracens. The nail is no longer visible; a plaque on the entrance door commemorates the event. The church is dedicated to St Michael the Archangel, who was invoked during the 6th-century defence of Naples.

The church is centrally located on Via dei Tribunali, a main street in Naples' old town district. It is easily accessible on foot from the historic center and situated near other notable sites.

The name "a Segno" comes from the nail fixed in the church threshold to mark the limit of the barbarian advance, Lombard for some sources and Saracen for others. The nail itself is gone; a plaque on the entrance door is what remains to recall the episode.