There is growing enthusiasm towards the role of smartphone app-based interventions in the management of insomnia and related sleep problems. A considerable number of apps designed to address insomnia have been developed in recent years, and randomized controlled trials (RCTs) have begun to explore their efficacy. We conducted a meta-analysis investigating the effectiveness of apps for insomnia and sleep disturbances. From 19 RCTs, we identified significant pooled effect sizes for the primary outcomes of self-reported insomnia (g = 0.60; 05 % CI = 0.44, 0.76; NNT = 4.8) and sleep disturbances (g = 0.70; 95 % CI = 0.58, 0.83; NNT = 4.1) in favour of apps over control conditions. These effects remained robust when restricting the analyses to trials that delivered a placebo control, received a lower risk of bias rating, and had a larger sample size. Significant pooled effects in favour of apps were also observed for secondary outcomes of night time awakenings (g = 0.56), total sleep time (g = 0.33), and sleep onset latency (g = 0.32), but non-significant effects emerged for daytime sleepiness, dysfunctional beliefs about sleep, sleep efficiency, sleep hygiene, and wake after sleep onset. The pooled dropout rate from app conditions was 13.1 % (95 % CI = 8.3, 20.0), which was significantly higher than control conditions (OR = 1.78, 95 % CI = 1.39, 2.28). Findings suggest that stand-alone app-based interventions can effectively address insomnia and sleep disturbances, and may play an important role in the management of these symptoms.