MRL may refer to: Magnetic Reference Laboratory, an American company that makes and sells Calibration Tapes Mineral Resources Limited, Australian mining company Official Monster Raving Loony Party, a UK political party Montana Rail Link, a US railroad Merck Research Laboratories, an American pharmaceutical company Technology related: Manufacturing readiness level, a measure of the maturity of the manufacturing readiness of an object of technology related to Technology Readiness Level (TRL) Maximum residue limit, a trading standard, usually for pesticide residues on foodstuffs Media resource locator, a URI for multimedia Multiple rocket launcher Murphy Roths large, a strain of mouse, having remarkable tissue regeneration abilities Machine room-less elevators