MM or variants may refer to:

• 2000 (number) in Roman numerals
• Million in some financial contexts
• Megametre (Mm)
• Millimetre (mm)
• Millimolar (mM), a unit of concentration of a solution
• Minimax or maximin, a decision rule
• Modified Mercalli scale for the intensity of earthquakes
• Momme, a unit of textile measurement
• Moving mean or moving average, a statistical calculation

.mm is the Internet country code top-level domain (ccTLD) for Myanmar (officially the Republic of the Union of Myanmar). It was assigned in 1997. Prior to 1989, the ISO 3166 alpha-2 code for Burma was BU, but no .bu ccTLD was assigned.

A computer virus is a malware program that, when executed, replicates by inserting copies of itself (possibly modified) into other computer programs, data files, or the boot sector of the hard drive; when this replication succeeds, the affected areas are then said to be "infected". Viruses often perform some type of harmful activity on infected hosts, such as stealing hard disk space or CPU time, accessing private information, corrupting data, displaying political or humorous messages on the user's screen, spamming their contacts, logging their keystrokes, or even rendering the computer useless. However, not all viruses carry a destructive payload or attempt to hide themselves—the defining characteristic of viruses is that they are self-replicating computer programs which install themselves without user consent.

is a Japanese light novel series by Akinari Matsuno, with illustrations provided by the group QP:flapper made up of Tometa Ohara and Koharu Sakura. Media Factory published 12 novels under their MF Bunko J imprint between February 2007 and September 2010, including two side story volumes. The series was left unfinished due to the author's death on April 18, 2011. A manga adaptation by Issei Hyoju was serialized between the September 2008 and February 2012 issues of Media Factory's Monthly Comic Alive. A drama CD adaption was released by Edge Records on March 24, 2010 and its first-press limited edition came with a bonus CD. A 12-episode anime adaptation produced by Xebec aired between October and December 2010. Sentai Filmworks released the anime series on English-subtitled DVD in North America in September 2011, and then re-released it in February 2014 with an English dub on both DVD and Blu-ray.

Among Linux kernel developers, the -mm tree refers to a version of the kernel source code maintained by Andrew Morton.