An apparatus and method for controlling a multi-band antenna in a mobile communication terminal are provided. An apparatus for controlling a multi-band antenna in a mobile communication terminal includes a modem, an antenna unit, a Radio Frequency (RF) processing unit, and a switch module. The modem outputs at least one control signal corresponding to a target frequency band. The antenna unit changes a resonance frequency of the antenna according to the at least one control signal. The RF processing unit includes a plurality of transmission/reception (TX/RX) paths and processes TX/RX signals. The switch module connects the antenna to one of the TX/RX paths according to the at least one control signal.