Mobile infantry is a military term and usually refers to infantry units equiped with vehicles.

Before the development of railroads in the 19th century, infantry armies got to the battlefield by walking, or sometimes by ship. In the 1890s and later, some countries used bicycle infantry, but the real revolution in mobility started in the 1920s with the use of motor vehicles, resulting in motorised infantry. Action in World War II demonstrated the importance of protecting the soldiers while they are moving around, resulting in the development of mechanized infantry that uses armoured vehicles for transport.

Some cavalry units and doctrines which emphasised that horses were to be used only as means of transportation, and soldiers dismount before battle, can be considered more as mobile infantry then cavalry as well, although this distinction is rather blurred.

Modern-day infantry is supported by armoured fighting vehicles, artillery, and aircraft, but are still the only kind of military force that can take and hold ground, and thus remain essential to fighting wars.