The name Tiago originated from the Latin name Jacobus, which was derived from the Hebrew name Ya'aqov. The name Ya'aqov itself was a Biblical name from the Old Testament, where it referred to one of the patriarchs of the Israelites. In the New Testament, the name appears as Iakobos in Greek, and Jacobus in Latin.

The name Tiago is the Portuguese form of the name Jacobus. It first appeared in Portugal during the Middle Ages, when the Latin form of the name was widely used across Europe. The name gained popularity in Portugal due to the veneration of Saint James the Great, one of the apostles of Jesus Christ, whose remains were believed to be buried in Santiago de Compostela in Spain.

One of the earliest recorded examples of the name Tiago in Portugal dates back to the 13th century. A nobleman named Tiago Pires de Vasconcelos was mentioned in historical records from that period. In the 15th century, a famous navigator and explorer named Tiago Cão explored the west coast of Africa and is credited with discovering the Congo River.

During the 16th century, a Portuguese Jesuit priest named Tiago Rodrigues was sent as a missionary to Japan, where he became one of the first Europeans to study the Japanese language and culture. In the 17th century, a Portuguese painter named Tiago Fernandes was known for his works depicting religious themes.

Another notable figure with the name Tiago was Tiago Rodrigues de Bivar, a Portuguese military officer who played a significant role in the Portuguese Restoration War against Spain in the mid-17th century. In more recent history, Tiago Splitter, a Brazilian professional basketball player who was born in 1985, played for several NBA teams and won an NBA championship with the San Antonio Spurs in 2014.