The aim of the work reported herein was to investigate anisotropy in the temperature rise occurring on the surface of Scots pine (Pinus sylvestris L.) during adsorption. The temperature increase on the transverse, radial and tangential surfaces of small wood specimens during adsorption was measured by thermal imaging. The experiments were conducted in a purpose-built humidity chamber facilitating the accurate control of the internal relative humidity (RH). It was found that the temperature rise on initially oven-dry wood surfaces exposed to a RH of 95% was anisotropic, with a maximum temperature increase of around 4 °C occurring on the transverse surface and around 1 °C on both the radial and tangential surfaces. Additionally, it was observed that the technique reported can be used to accurately measure the temperature change arising from sorption, thus providing reliable information about the behaviour of wood. This information is vital if the effects of the enthalpy change occurring during water vapour sorption are to be correctly considered in building physics models and the potential to reduce energy consumption in buildings fully realised.