MNS may refer to:

• Maharashtra Navnirman Sena, Indian political party
• The Malaysian Nature Society
• Maki-Nakagawa-Sakata matrix in particle physics
• Ministry of National Security of several countries
• Minneapolis, Northfield and Southern Railway, reporting mark
• Mirror neuron system
• Mission Need Statement
• MNS antigen system, a variant blood group
• Monday Night Soccer, an Irish television programme
• Movement for a New Society
• National Syndicalists (Portugal), Movimento Nacional-Sindicalista
• Manganese(II) sulfide, chemical symbol MnS
• Mansi language, by ISO 639-3 language code