The Ibiraçu region belonged to the old municipality of Santa Cruz (current Aracruz).

In 1877, the engineer Aristides Guaraná received Italian immigrants to work on his lands in Córrego Fundo. These immigrants founded a settlement that went through several names until it became Ibiraçu, in 1943.

The municipality was created in 1891 with the name Guaraná. The following year, it was renamed Pau Gigante. In its administrative formation, it included the districts of Acioli, João Neiva, and Pendanga. In 1988, Acioli and João Neiva emancipated themselves, forming the municipality of João Neiva. Since then, Ibiraçu is constituted by two districts: Ibiraçu and Pendanga.

Demonym: ibiraçuense.