Background: Insomnia is a prevalent problem which often leads to a reduced quality of life and diminished work productivity. Only a minority of patients are treated with effective non-pharmacological therapies. A self-help intervention might offer an inexpensive and more accessible alternative to face-to-face treatment. Methods: We conducted a meta-analysis of randomized controlled studies examining the effects of self-help interventions for insomnia, identified through extensive searches of bibliographical databases. We examined the effects of self-help on different sleep outcomes, in comparison with both waiting lists controls and face-to-face treatments. Results: Ten studies with a total of 1000 subjects were included. The intervention did improve sleep efficiency (d=0.42; p<0.05), sleep onset latency (d=0.29; p<0.05), wake after sleep onset (d=0.44; p<0.05) and sleep quality (d=0.33; p<0.05) but not total sleep time (d=0.02; p>0.05). The sleep improvements were maintained over the longer term. Symptoms of anxiety and depression also decreased after self-help (d=0.28; p<0.05 and d=0.51; p<0.05, respectively). Although based on a very limited number of studies, the face-to-face treatments did not show statistically significant superiority to the self-help treatments. The effect sizes associated with self-help treatments might be overestimated due to publication bias. Conclusions: The effects of self-help treatments are small to moderate. Nevertheless, they might constitute a useful addition to existing treatment options especially when integrated in a stepped care approach.