A thermally controlled plasmonic substrate supporting surface plasmon polaritons in contact with a liquid crystal medium is presented. The platform offers a spectral tuning range ∼18.7 nm by controlling the refractive index of the liquid crystal medium within the nematic phase in a temperature range of 18 °C. The abrupt transition between nematic and isotropic phases also enables a spectral tuning as large as 12 nm with only ∼1 °C.