This article summarizes the evidence as regards the effectiveness of therapy for grammar for school-aged children with language impairments. I first review studies focusing on specific areas of grammar (both expressive and receptive targets) and then studies aiming to improve language more generally, several of which focus more on the effectiveness of different methods of delivery. I conclude that while there is a growing body of evidence in this area, there are still many gaps. The most concerning gap is the small amount of evidence of effectiveness of intervention for children with receptive as well as expressive language impairments. The evidence to date seems to indicate that these children need specialist, intensive help in order to make progress with their language. Further research is also needed to consider the relative impact of different types of interventions (or their combination) on children of different ages and with different language profiles, including establishing the most effective and/or cost-effective methods of delivery of these interventions.