The Ier is a river in Romania and Hungary.
Ier may also refer to:
- Ier, the Romanian name for the river Száraz-ér in Romania and Hungary
The acronym IER may refer to:
- Instance équité et réconciliation, a Moroccan human rights commission
- Institute of Education and Research
- International Economic Review, an economics journal
- Interurban Electric Railway, a division of the Southern Pacific Railroad in the U.S.
- Institute for Energy Research, a nonprofit public policy think tank
- New South Wales Institute for Educational Research, an Australian educational research institute
- Individual Electoral Registration, a reform of electoral registration in the United Kingdom proposed by the Coalition Government
- IER (company), a subsidiary of the Bollore group which owns Source London and electric car charging infrastructure