During Roman times the settlement was known as Astigi. Caesar ordered the town's fortification and refounded it as a Julian colony. According to Pliny the Elder who wrote in the 1st century AD, it was the rival of Cordova and Seville.

After the Romans, it was ruled by successively by Suevs and Visigoths. It was also from an early date the seat of a diocese. St. Fulgentius (died before 633), was named to the see by his brother Isidore of Seville.

In 711, Écija was conquered by an Islamic army on its way to Córdoba. Capital of an extensive Kūra, Écija preserved its condition as a centre of high agricultural productivity.

The place was seized by Christians in 1240. The proximity to the Nasrid Kingdom of Granada turned Écija into a border town. Most of the mudéjar population was expelled in 1263. The Jewish population suffered the antisemitic revolt initiated after the assault on the jewry of Seville in June 1391, that spread across Andalusia. During the 15th century, Écija was the third most important urban centre of the Kingdom of Seville after Seville and Jerez. Estimations for the 15th century yield a population of about 18,000 (today 40.000).

The Camino de Santiago is everywhere