M34 or M-34 may refer to:
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M34 (New York City bus) SBS and
M34A (New York City bus) SBS, two New York City Bus routes in Manhattan
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M34 grenade
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M34 cluster bomb
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M-34 (Michigan highway), a road in the United States of America
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M34 highway (Tajikistan), a road connecting Dushanbe and the Anzob Pass
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M34 (Cape Town), a Metropolitan Route in Cape Town, South Africa
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M34 (Johannesburg), a Metropolitan Route in Johannesburg, South Africa
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M34 (Pretoria), a Metropolitan Route in Pretoria, South Africa
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M34 (Durban), a Metropolitan Route in Durban, South Africa
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Mikulin M-34, the Soviet Union's first indigenous mass-produced liquid-cooled aircraft engine
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Messier 34, an open cluster in the constellation Perseus
* M34 2½ ton cargo truck, a variant of the United States Army
M35 2½ ton cargo truck
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M34 (keelboat), a French sailboat design
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