This chapter presents two distinctly different thermometry techniques for near-field temperature measurements: nano-optical surface plasmon resonance (SPR) imaging thermometry and nanomechanical cantilever thermometry. SPR thermometry is based on the dependence of surface plasmon polariton (SPP) resonances on the refractive index (RI) or temperature in the near-field region, that is, within an order of 100 nm into the fluid from the solid interface. In contrast, nanomechanical thermometry is based on the correlation of the thermal Brownian motion of the microcantilever with the surrounding fluid temperature and uses a probe to measure the near-field microscale temperatures down to 5 μm from the solid surface. Note that nano-optical thermometry is a non-intrusive technique based on surface plasmon reflectance, which is known to have the most sensitive RI detection capabilities, whereas nanomechanical thermometry is an intrusive technique but potentially overcomes the diffraction limit of the conventional optical technique.