Summary The effects of a fire on plant community structure were examined in a remnant Gidgee (Acacia cambagei) and Brigalow (Acacia harpophylla) woodland infested with the naturalized exotic, Buffel Grass (Cenchrus ciliaris) in central Queensland. Fifteen months after the fire, burnt areas had about half the basal area of living trees and more than twice the cover of Buffel Grass and Parthenium Weed (Parthenium hysterophorus) as unburnt areas. This is consistent with the idea that Buffel Grass invasion, which increases ground fuel loads in Acacia woodlands, is facilitated by burning, producing positive feedback between Buffel Grass and fire. The result is accelerating remnant degradation, making the interaction between Buffel Grass and fire an important target for management measures. Fire-breaks and fuel reduction strategies including periodic intense grazing and canopy enhancement have potential to reduce the impact of Buffel Grass invasion, but long-term community survival will probably require effective control of Buffel Grass. The impact of weed invasion within remnant vegetation is clearly a complex issue but the simple ‘case study’ approach employed here can both increase and communicate understanding.