Montjoi (French pronunciation: [mɔ̃ʒwa] ⓘ; Occitan: Montjòi) is a commune in the Tarn-et-Garonne department in the Occitanie region in southern France The inhabitants are called Montjoviens .

Situated between the valleys of the Lot and Garonne rivers, Montjoi is an old Bastide village founded in 1256–1257 with half-timbered houses made of Quercy limestone and red brick from the local area, located on a rocky outcrop offering views over the surrounding countryside.

The town is located 16 km north-north-east of Valence-d'Agen, in the Quercy blanc region overlooking the Séoune River.

[3] Perched on its rocky peak, a former castrum (Latin for Castle), Montjoi was founded in the 13th century by the Lord of Penne and Alphonse de Poitiers, count of Toulouse, who made it a royal bastide around 1255–1256.

[6] The area economy is mainly agricultural with mixed farming including cereals, livestock, onions, strawberries, fruits, nuts, etc.