Prices received by Australian wheat farmers have increasingly depended on grain quality, especially protein concentration. This concentration depends on various agronomic and physical factors including weed competition. In this paper a model of weed management in the presence of grain quality premiums is presented. Two types of quality premium are examined: a continuout linear payment schedule and a discontinuous "stepped" schedule with substantial premiums for quality levels above a critical level. The model is applied to an analysis of the impact of protein premiums on optimal management strategies for a particular weed in Western Australia. It is found that the impact of protein premiums on optimal weed management is likely to be very small indeed, even if premiums were substantially increased above current levels.