Stuttering is a speech disorder that begins during the first years of life and impairs verbal communication. Those who stutter are at extreme risk of social phobia. The bulk of evidence for treatment efficacy is in nonrandomized trials. Two randomized controlled trials (RCTs) have been reported for verbal response contingent stimulation treatments for preschool children who stutter. A meta-analysis of RCTs and randomized controlled experimentation show an odds ratio of 7.5 for this treatment. There have been two RCTs of speech rehabilitation for stuttering in adults and adolescents, and one RCT of a cognitive behavior therapy intervention for social anxiety. Consensus recommendations are for verbal response contingent stimulation for preschool children, and a form of speech rehabilitation known as speech restructuring for adults. Confidence is guarded at present about recommendations for cognitive behavior therapy intervention, although a single published RCT is most encouraging.