Unsustainable patterns of tourist behavior produce a massive environmental burden. Nevertheless, it is unknown which behavioral strategies can be implemented to foster resource-efficient behavior in customers of leisure and travel services. This article aims to identify and summarize the evidence about the interventions which have been tested to promote sustainable hotel guest behavior. Electronic searches were performed in the main databases from inception to September 2016. Papers deemed eligible for inclusion were experimental field studies, reporting factual changes in guest behavior. The final sample was composed of nine papers comprising 13 studies in a total of 5,859 hotel stays. Results showed that all included interventions targeted towel reuse. Five different types of interventions were identified including environmental appeals, messages prompting commitment for conservation, donation to charity, social norms, and nudges. Only the last two forms of interventions (social norms: effect size [ES] = −0.25, 95% confidence interval [CI] = [−0.39, −0.12], p = .004 and nudges: ES = −0.43, 95% CI = [−0.72, −0.13], p = .009) showed significant positive effects in promoting towel reuse. Particularly regarding social norms, our work shows an effect weaker than reported in previous meta-analyses but consistent (low between-study heterogeneity) in producing modest increases in the levels of towel reuse.