Multiband antenna decoupling networks and systems including multiband antenna decoupling networks are provided herein. A multiband decoupling network is connected to two or more closely spaced antennas. The multiband decoupling network includes lumped components and is reconfigurable to decouple the two or more antennas at a plurality of distinct communication frequency bands. The multiband decoupling network may include tunable lumped components and be reconfigurable through tuning the tunable lumped components. A pi network may be used for the multiband decoupling network. At least one separate impedance-matching network may also be used to match the input impedance of the multiband decoupling network to the output impedance of transmission lines leading to the multiband decoupling network.