UM or um may refer to:

Universities

* U of M (disambiguation) or UM, abbreviation for various universities

Businesses

* Universal McCann, a global advertising and media agency * United Motors Company, a former name of American automotive parts supplier ACDelco * Air Zimbabwe (IATA code UM)

Science and technology

* .um, the Top-Level Domain for United States Minor Outlying Islands * Um interface, the air interface for the GSM mobile telephone standard * Micrometre (μm), sometimes written as "um" in limited character sets * Unified Model, a global numerical weather prediction model * Ultrarapid metabolizer, a term used in pharmacogenomics to refer to individuals with substantially increased metabolic activity * User manual, a document or manual intended to give assistance to people using a particular system * Utilization management, the evaluation of the appropriateness, medical need and efficiency of health care

Other uses

* Um (Korean surname) * "Um", an exclamation or Filler (linguistics), filler in spoken conversation * Um (cuneiform), a sign in cuneiform writing * Umphrey's McGee, a jam band * Unofficial magistrate, as a postnominal * Unified Messaging, in marketing * United States Minor Outlying Islands (ISO 3166 code UM) * Union for the Mediterranean, an intergovernmental organization of 43 countries from Europe and the Mediterranean Basin * Uttaradi Math, a Hindu matha (monastery) * United Methodist, a religious organization {{disambiguation