Moisture is one of the main causes of defects in buildings, compromising not only the durability of materials and components, but also the indoor comfort and health conditions of users. Infrared thermography (IRT) is a technique that has great potential for mapping humidity in buildings but quantitative criteria that correlate differences in surface temperatures with the moisture content are lacking. This paper presents the results of laboratory tests carried out using IRT and the gravimetric method to assess the correlation between the temperature gradient between the dry zone and the wet zone of mortar specimens and their respective moisture content, considering three conditions/scenarios of air temperature and relative humidity: (i) 20 ºC and 70%, (i) 25 ºC and 60%, (iii) 15 ºC and 80%. The results show that there is a relation between the two values for the three tested scenarios. It was also found that the order of magnitude of the temperature gradient that corresponds to higher values of moisture content is different for the different scenarios analysed.