Montesardo is a frazione (transl. village) in the comune of Alessano in the province of Lecce in the Apulia region, Italy. As of the 2001 census, it has a population of 1,369. It is 59 km (37 mi) from Lecce, just over 10 km (6.2 mi) from Leuca, and 1 km (0.62 mi) from the comune capital of Alessano.

The village is located 184 m (604 ft) above sea level. Montesardo is the third highest area in the province of Lecce after Serra dei Cianci [it] and Monte Sant'Eleuterio. The village developed on the southern continuation of the Serra dei Cianci mountain, so the village is sometimes referred to as "Serra di Montesardo". Montesardo is crossed by state highway 275 [it] (SS 275) of Santa Maria di Leuca.

Montesardo has a Mediterranean climate, with mild winters and hot summers. The coldest month is January, with an average temperature of 9 °C (48 °F), and the hottest month is August, with an average temperature of 25.1 °C (77.2 °F). The average amount of rainfall per year is 676 mm (26.6 in). Rainfall is at a minimum during spring and summer and peaks during autumn and winter.

The comunes of lower Salento, including Montesardo, are weakly affected by winds due to protection from Serre Salentine [it] (Salento greenhouses) – elevated areas that create a shield system.

Records of Montesardo begin in the 16th century. In his work De situ Japigiae [it], Italian scholar Galateo describes an "oppidum mediocris magnitudinis" with a large circular wall and visible ruins of ancient houses located on a hill called "Mons Arduus", about seven miles away from Leuca. Galateo also recalls that the town was called "tracheion oros" by the Greeks, interpreted in Latin as "Mons asper" or "arduus", meaning steep or rugged mountain.

In the 19th century, historian Luigi Tasselli, in his work Antichità di Leuca (Antiquity of Leuca), hypothesized a Greek origin of the city based on Galateo's writing; in La corografia fisica e storica di Terra d'Otranto (The physical and historical chorography of Terra d'Otranto), he stated that the Byzantine Greeks would then have translated the Latin name into "trachina", i.e. the "tracheion oros" referred to by Galateo. Over time, the area would have taken the name "Monsarduus" from Latin, from which the current name of Montesardo would have derived.

It was previously hypothesized that there may have been an earlier ancient settlement at the site of the current inhabited area of Montesardo based on aerial photos and a reconnaissance of the terrain which revealed a defensive route of about 3.6 km (2.2 mi) in length. Archaeological research has since identified traces that confirm the existence of this settlement. A hint of the presence of an ancient settlement in the area was given when a tomb was found in 1953 in a rocky bank in Alessano. In 1997, the first systematic excavation was carried out, which revealed the remains of a large building that had been built with blocks of tuff. During construction excavations near the Romasi Castle in the second half of the 1980s, ceramic material was recovered, giving an indication of a population in the area between the 9th and the 1st century BC. Additionally, a stretch of wall at the base of the Romasi castle, estimated to have been built between the 4th and 3rd centuries BC, uses a stone building technique also found in the nearby city of Vereto [it].

After the fall of the Western Roman Empire, Montesardo was used as a fortress due to its bastions, fortified castle, and circle of walls interspersed with towers. These walls and towers were demolished in 1867. Montesardo was also a seat of important schools of mathematics, philosophy, and music. During World War II, the land was occupied by German troops.