OML

OML may refer to:
 * Old Main Line (disambiguation), various meanings in transportation
 * Old Mutual, an international insurance company
 * One More Light, an album by American musicians Linkin Park
 * Order of Merit List, for the U.K. Order of Merit
 * Outer mold line, an aeroshell's outer surface, mainly used in the context of aviation, such as in spacecraft boilerplates
 * OML, the Indian Railways station code for Omalur Junction railway station, Salem, Tamil Nadu
 * OML (computer format) (Outline Markup Language) is an XML format for outlines