Previous publications have reached different conclusions about the balance between the socioeconomic benefits of tilapia introduction for aquaculture and capture fisheries, and the potential negative impacts of these species on ecosystem services such as the provisioning of food, habitat, and water quality. This review (1) provides a new estimate of the global scale of tilapia introduction and the reported occurrence of impacts to ecosystem services; (2) assesses whether reported changes to ecosystem services differ among species, regions and type of ecological effect reported; and (3) determine how perceptions of tilapia introduction are related to the reported occurrence of ecological effects and/or the contribution of tilapia to countries’ economies. Feral tilapia populations now exist in at least 114 countries. The majority of research is consistent with the occurrence of ecological change as a result of tilapia introduction, regardless of species or region of study, but there are important regional influences including the economic contributions of tilapia. There is an increasing recognition that introductions provide both significant benefits and considerable but not fully documented harm to ecosystem services. Stakeholders should consider both ecological effects and socioeconomic context, such as reviewed here, in making decisions about the introduction of tilapia.