M0 (M followed by zero) or M-0 may refer to:

• Aero Mongolia, an airline based in Ulaanbaatar, Mongolia (IATA designation M0)

• Megyeri Bridge (formerly known as Northern M0 Danube bridge), a bridge crossing the Danube River
• M0 motorway (Hungary), a ringroad around Budapest

• M0 (economics), the monetary base regarding the money supply
• MØ (born 1988), Danish singer and songwriter
• M0, a non-small-cell lung carcinoma staging code for no distant metastasis
• M0, a type of macrophage, a type of defensive phagocytic cell in living things
• Hayes command set M0, a command for turning a modem speaker off
• Measure zero, or M0, the size of the null set
• M0 macrophage, a phenotype of macrophage

• 0M (disambiguation)
• Mo (disambiguation)
• μ₀, the vacuum permeability
• M_☉, the solar mass