MMN may refer to:

• Mismatch negativity
• Multifocal motor neuropathy
• Mystery meat navigation
• Matematikmaskinnämnden, the Swedish Board for Computing Machinery
• Mamanwa language, a Central Philippine language (ISO 639-3 code)
• Ticker symbol for Mannesmann AG, a German corporation

• Mandeville, Jean de
• Mandeville (LA)
• Mandeville place
• Mandeville Place
• Mandeville School
• Mandeville's paradox
• Mandevillia
• Mandgelis Document
• M and G Records
• Mandhatri
• Mandheling
• Mandholi
• Mandhra
• Mandian
• Mandiana
• Mandiana Prefecture
• Mandiana Prefecture, Guinea
• Mandianism
• Mandian, Pakistan
• Mandias
• Mandias the Terrible
• Mandi Bahauddin
• Mandi Bahauddin District
• Mandi Bamora
• Mandible (arthropod mouthpart)