Bacabeira is a municipality in the state of Maranhão in the Northeast region of Brazil.
The municipality contains a small part of the Baixada Maranhense Environmental Protection Area, a sustainable use conservation unit created in 1991 that has been a Ramsar Site since 2000. The municipality contains part of the Upaon-Açu/Miritiba/Alto Preguiças Environmental Protection Area, created in 1992.