This area has been inhabited since ancient times. A Neolithic necropolis has been found in the somewhat inaccessible site known as Los Castillejos, and the Arab past of the village is well documented.

Its Arab name was Qazya al-intisat, meaning Happiness, and it is known to have possessed several quarters, with mosques, a cemetery, etc. The present-day church (16th century) was built on the site of the principal mosque, the aljama.

During the reign of Philip II, the Moriscos (the Moors converted to Christianity) were expelled and the region was resettled by immigrants from other parts of the peninsula, as recorded in the Registers of Surveys and Settlements, now kept in the Town Hall and considered a part of the local heritage.

Lentejí today is dedicated to agriculture, and the most important crops are subtropical ones, such as medlars, custard apples and avocados. Other crops are also grown, though these are of lesser importance, and are mainly for home consumption; they include other fruit crops, such as oranges, lemons and pears, and vegetables.