The disclosure relates to a method for continuous acetylation of wood elements. The acetylation is conducted with an acetylation medium at a pressure of at least 1.5 barg in a substantially oxygen free environment. Alternatively, the method includes the steps of: (a) feeding wood elements in a substantially oxygen free environment to a continuous acetylation reactor, and (b) treating the wood elements with an acetylation medium in the continuous acetylation reactor under wood acetylation reaction conditions, at a pressure of at least 1.5 barg. The process can acetylate wood elements to a high acetyl content in an efficient way, without compromising on the quality of the material. The acetylated wood elements can be used in the production of medium density fibreboards with superior qualities such as dimensional stability and durability.