Handheld electronic devices and methods involving tunable dielectric materials are provided. In this regard, a representative device includes: a transceiver operative to selectively transmit and receive electrical signals; an antenna assembly electrically connected to the transceiver, the antenna assembly having anisotropic dielectric material operative to exhibit a change in dielectric constant responsive to an applied electrical signal; and a dielectric tuning system operative to automatically and selectively apply a first signal to the antenna assembly to change the dielectric constant of the anisotropic dielectric material to alter a resonant frequency and efficiency tuning of the antenna.