M99

M99 or M-99 may refer to:

Places

 * M-99 (Michigan highway), a state highway in south central Michigan
 * Messier 99, an unbarred spiral galaxy approximately 60 million light-years away in the constellation Coma Berenices
 * M99 road (Johannesburg), Metropolitan route in the City of Johannesburg, South Africa

Rifles

 * Barrett M99, a sniper rifle
 * Zijiang M99, a Chinese anti-materiel rifle

Tranquilizer

 * Etorphine (a.k.a. Immobilon or M99), a veterinary tranquilizer