In 1921 Joseph Maiden described "Acacia westonii" from the northern and western slopes of Mount Jerrabomberra near Queanbeyan in New South Wales. He felt it was similar to, but distinct from, "A. pycnantha" and was uncertain whether it warranted species rank. His colleague Richard Hind Cambage grew seedlings and reported they had much longer internodes than those of "A. pycnantha", and that the phyllodes appeared to have three nectaries rather than the single one of the latter species. It is now regarded as a synonym of "A. pycnantha".