Nettle is one of the most important and abundant medicinal plants that is available seasonally. Increasing the shelf life, along with achieving the quality characteristics expected by the consumer markets, is one of the most important goals of the drying process and is one of the influencing factors on the process time as well as the quality characteristics. The purpose of this research is to find a suitable mathematical model to describe the experimental drying process, to evaluate the diffusion coefficient, to obtain the activation energy to determine the thermodynamic properties during the nettle drying process. Nettle leaves with initial moisture content (2.15 ± 0.05 kg of water/kg of dry matter) in an infrared dryer at three temperatures of 40, 45 and 50 degrees Celsius and with two times of ultrasonic pretreatment for They were dried for 5 and 10 minutes until reaching a constant weight. The best model to describe the nettle drying process was chosen by Midilli et al. The moisture diffusivity coefficient of nettle increased with increasing drying temperature and duration of ultrasound treatment. The activation energy during drying of nettle was 11.45 - 40.54 kJ.mol-1. Enthalpy and entropy decreased with increasing drying temperature and duration of ultrasound pretreatment, while Gibbs free energy increased. Enthalpy value changed between 37.8-76.94 kJ.mol-1, entropy value between -178.00 and -73.18 kJ.mol-1 and Gibbs free energy value between 60.85-66.28 kJ.mol-1.