Amir Ordacgi Caldeira (born 1950 in Rio de Janeiro) is a Brazilian physicist.
He received his bachelor's degree in 1973 from the Pontifícia Universidade Católica do Rio de Janeiro, his M.Sc.
In 1984 he did post-doctoral work at the Kavli Institute for Theoretical Physics (KITP) at University of California, Santa Barbara and at the Thomas J. Watson Research Laboratory at IBM.
He was the recipient of the Wataghin Prize, from Universidade Estadual de Campinas, for his contributions to theoretical physics in 1986.
Caldeira's research interests are in theoretical condensed matter physics, in particular quantum dissipation and strongly correlated electron systems.