Martinsicuro is a town and comune in province of Teramo, Abruzzo, central Italy. It is located on the right of the mouth of Tronto River.
Remains of a Bronze Age (10th-9th century BC) settlement were found in the communal territory, on a hill overlooking the Tronto river. At the river's mouth existed Truentum, remembered by Roman writer Pliny the Elder as part of the Roman region of Picenum, and attributed to the Liburni tribe. After the Roman conquest in the 3rd century BC it became a municipium and later was reached by the Via Salaria.
In the 5th century AD it became a Christian bishopric seat. It was conquered by the Lombards in the wake of the fall of Fermo in 580, but in the subsequent centuries most of the inhabitants moved to other centres in the mainland. In the 16th century the Spaniards built here two watchtowers, around which a small borough grew.
Main sights 
- Tower of Charles V (1547). Since 2009 it houses an archaeological museum.
International relations 
Twin towns — Sister cities 
Martinsicuro is twinned with: