It is important the spread of thermal modification as a process that aims to improve undesirable properties of woods with low commercial value. Better results can be obtained by combining processes and adding hydrophobic agents such as oils and waxes. The objective of this study was to evaluate the effect of paraffin-thermal modification on the hygroscopicity and dimensional stability of Nectandra dioica Mez wood. The combined treatment was applied at two temperatures (190 °C and 210 °C) for 150 min. The samples were subjected to three immersion-drying cycles to evaluate the water absorption (WA) and the anti-swelling efficiency (ASE). Dimensional stability increased proportionally to the temperature intensity, increasing with the addition of paraffin. The opposite behavior was observed for WA, recording results of only 17.03% in the most intense treatment (210 °C + paraffin). In general, the best results were for paraffin-thermally modified wood at 210 °C. Thermal modification with paraffin is recommended, as it will result in some advantages in terms of dimensional stability and water repellency, making it an option for wood in various applications.