Mier might refer to one of the following:
- Mier, Asturias, a parish in northern Spain
- Ciudad Mier, a city and municipality in northern Mexico
- Mier Local Municipality, a municipality in South Africa's Northern Cape province
- Servando Teresa de Mier, a Roman Catholic priest of New Spain
- Manuel Mier y Terán, a Mexican general
- Francisco Mier y Torre, Governor of the New Kingdom of León from 1710 to 1714
- Henry Mier, an Uruguayan footballer
- Manchester Independent Economic Review
- Mier Expedition