Duomo, Gothic Revival cathedral in Mortegliano, Italy.

The Duomo is a Gothic Revival cathedral in Mortegliano, a small town in the Friuli-Venezia Giulia region of northern Italy. It has stained glass windows, several chapels, and religious motifs throughout its interior.

The first stone was blessed on 23 April 1864, after the fifteenth-century church of San Paolo and a defensive tower were demolished. Andrea Scala's octagonal Gothic Revival design was built in stages; the eight-sided tent roof was only completed in 1907, and the church was finished in 1955. The 113-metre reinforced-concrete bell tower by Pietro Zanini followed in 1957–1959.

The name Mortegliano likely derives from the Latin "mortarium", referring to a mortar or a place where mortar was made. The parish is dedicated to the Holy Trinity, while the church itself honours the apostles Peter and Paul, whose figures appear in the stained glass of the apse windows installed in December 1913, together with the Redeemer.

The cathedral stands in the center of Mortegliano and is easy to reach on foot from most parts of the town. When religious services are in progress, visitors are expected to dress modestly and move quietly.

The bell tower of the Duomo is tall enough to be seen from a considerable distance, becoming a reference point in the flat Friulian landscape. It was built after the main church was already finished, giving it an almost separate identity within the complex.