Abstract: This study investigates the sorption behaviour of thermally and chemically modified selected wood species. Wood samples of dimensions 20 mm × 20 mm × 20 mm were used in this study. The samples were oven dried and thermally treated at temperatures of 160°C, 180°C and 200°C for 30 minutes. Another set of wood samples were prepared for chemical treatment (Acetylation) inside an oven at 80oC for 180 min. The colour varied from light cream to slightly brown at 160°C and very brown at 200°C for thermally modified wood. The color of the chemical modified wood changes from being yellowish of the untreated wood to pale yellow in colour. The percentage weight loss increases with temperature from 22.62% at 160°C to 26.46% at 180°C and 20.8% for Percentage Weight Gain (PWG). The average value of water absorption ranged from 8.60 to 16 %; 26 to 40.78 %; 35 to 50.35 % and 42.88 to 57.53 % for 1 hour to 78 hrs respectively. The value for the chemically modified wood ranged between 5.22 and 5.59 %, with RH of 97% and 7% having the lowest and highest value respectively. The study revealed that there was a reduction in the weight and density of thermally treated wood as a result of thermolysis and weight was gained after chemical modification.