MDL may mean:
- Mazagon Dock Limited, an Indian shipyard
- MdL (producer), an American music producer
- MDL (medium-density lipoprotein), a biochemical compound
- MDL (programming language), a derivative of the LISP language
- Memory Descriptor List, in computing, a map that allows virtual memory to be accessed by page
- Method Detection Limit, in analytical chemistry, the lowest quantity of a substance that can be distinguished from the absence of that substance
- MDL Information Systems, a scientific information management company originally known as "Molecular Design Limited"
- Military Demarcation Line, a truce border line between North and South Korea
- Minimum description length, a principle for inductive inference in information theory
- Fayyad & Irani's MDL method, a discretization method
- Michelle Dewberry Ltd, a British company founded by The Apprentice winner Michelle Dewberry
- Moldovan leu, the currency of Moldova
- Multidistrict Litigation, an American legal procedure for pre-trial consolidation of complex litigation
- Museum of Dartmoor Life, Oakhampton, Devon, England
- Roman numeral for 1550
- The filename extension (.mdl) for a Simulink model file
- MDL- Diamond Limited (Toronto Canada) one of Canada's leading diamond company