M
- Mackle-Thompson (1903)
- Macomber (1913)
- Macon (1915–1917)
- Madison (1915–1919)
- Magic (see Mondex-Magic)
- Mahoning (1904–1905)
- Maibohm (1916–1922)
- Mais (circa 1912)
- Majestic (1917)
- Malcolm (1900)
- Malcolm Jones (or Malcolm) (1914–1915)
- Malden Steam (1898, 1902)
- Manexall (1920) (see Cyclomobile)
- Manistee (1902)
- Marathon (1906–1914)
- Marble-Swift (1903–1905)
- Marion (1901)
- Marion (1904–1915; Marion-Handley 1916-1918)
- Marion Flyer (1910)
- Marmon (1902–1933)
- Marlboro (1900–1903)
- Marquette (1912)
- Marquette (1930)
- Marr (1903–1904)
- Marsh (1899–1905)
- Marsh (1920–1923)
- Marshall (1920–1922)
- Martin (1898–1900)
- Martin (1910)
- Martin (1928–1932)
- Martin-Wasp (see Wasp)
- Marvel (1907)
- Maryland (1907–1910)
- Maryland Steamer (1900–1901)
- Mason (1898–1899)
- Mason (1906–1914)
- Massillon (1909)
- Master (1907)
- Matheson (1903–1912)
- Maxim Motor Tricycle (1895; Maxim-Goodridge Electric 1908)
- Maxwell-Briscoe (1904–1913; Maxwell 1913-1925)
- Mayer (1899–1901)
- Mayfair (1925)
- Maytag (1910–1911)
- M.B. (1908–1911)
- McCue (1909–1911)
- McCurdy (1922)
- McFarlan (1909–1928)
- McGill (1917)
- McIntyre (1909–1915)
- McKay Steamer (1899–1902)
- Mecca (1915–1916)
- Med-Bow (see Springfield)
- Media (1899–1900)
- Mel Special (1918–1924)
- Menominee Electric (1915)
- Mercer (1909–1919)
- Mercury (1913–1914)
- Mercury (1918–1920)
- Mercury (1939–2010)
- Merit (1921–1922)
- Merkel (1905–1907)
- Merz (1914)
- Meteor (1900–1901)
- Meteor (1904–1905)
- Meteor (1908–1910)
- Meteor (1915–1930)
- Meteor (1919–1922)
- Metropol (1913–1914)
- Metropolitan (1922–1923)
- Metz (1909–1921)
- Metzger (see Everitt)
- Michigan (1903–1908)
- Michigan (1908–1914)
- Michigan Steamer (1901)
- Middleby (1909–1913)
- Midland (1908–1913)
- Midwest (see Highlander)
- Mier (1908–1909)
- Milac (1916)
- Milburn Electric (1915–1923)
- Miller (1911–1914)
- Mills (1876)
- Mills Electric (1917)
- Milwaukee Steamer (1900–1902)
- Minneapolis (see Colby)
- Mino (1914)
- Mitchell (1903–1923)
- Mitchell-Lewis (see Mitchell)
- Mobile (1900–1903)
- Model (1903–1907)
- Modoc (1912–1914)
- Mohawk (1903–1905)
- Moline (see Stephens or Illinois)
- Moline (1904–1913; Moline-Knight 1914-1919)
- Moller (1920–1922)
- Monarch (1905–1908)
- Monarch (1907–1909)
- Monarch (1914–1917)
- Mondex-Magic (1914–1915)
- Monitor (1909–1911)
- Monitor (1915–1922)
- Monroe (1914–1923)
- Moon (1905–1930)
- Moore (1906–1909)
- Moore (1916–1920)
- Mora (1906–1911)
- Morgan (1900–1902)
- Morris & Salom (1895–1897)
- Morrison Electric (1888–1895)
- Morriss-London (1919–1923)
- Mors (see American Mors)
- Morse (1902)
- Morse (1905–1906)
- Morse (1910–1916)
- Morse (1914–1916)
- Motor Bob (1914)
- Motorette (1911–1914)
- Moyea (1903–1904)
- Moyer (1911–1915)
- M.P.M. (1914–1915)
- Mueller (1896–1899; also Mueller-Benz)
- Multiplex (1912–1913)
- Muncie (see Warner)
- Muntz (1950–1954)
- Murdaugh (1901–1903)
- Murray (1902–1903)
- Murray (1916–1921; Murray-Mac 1921-1929)
Read more about this topic: List Of Defunct Automobile Manufacturers Of The United States