Temperature is a basic parameter influencing the behavior of systems in physics, chemistry and biology. From living cells to microcircuits, a wide range of cases require thermometry techniques that can be applied to reduced areas, offering sub-micrometric resolution and high accuracy. Since traditional thermometers cannot be applied in such systems, alternative tools have been specifically designed to measure temperature at the nanoscale; including scanning thermal microscopy, non-contact optical techniques or various types of luminescent nanoparticles. Each option presents interesting advantages, but also limitations that need to be considered and understood. We provide here an overview of the main currently available nanothermometry tools, discussing their pros and cons toward potential applications. (C) 2018 Elsevier Ltd. All rights reserved.