4A

4A or IV-A may refer to :
* 4A/OP, an operational fast and accurate radiative transfer model for the infrared
* Long March 4A, a Chinese rocket
* Region IV-A, a designation for Calabarzon province in Philippines
* Stalag IV-A, a German prisonners of war camp
* Texas Instruments TI-99/4A, a 1981 home computer
* Vermont Route 4A
* Air Kiribati IATA airline designator