Mosquitoes carrying endosymbiotic bacteria called Wolbachia are being released in mosquito and arbovirus control programs around the world. Open field releases of Wolbachia-infected male mosquitoes have achieved over 95% population suppression, while the replacement of populations with Wolbachia-infected females is self-sustaining and can greatly reduce local dengue transmission. Despite many successful interventions, significant questions and challenges lie ahead. Wolbachia, viruses and their mosquito hosts can evolve, leading to uncertainty around the long-term effectiveness of a given Wolbachia strain, while few ecological impacts of Wolbachia releases have been explored. Wolbachia strains are diverse and the choice of strain to release should be made carefully, taking environmental conditions and the release objective into account. Mosquito quality control, thoughtful community awareness programs and long-term monitoring of populations are essential for all types of Wolbachia intervention. Releases of Wolbachia-infected mosquitoes show great promise, but existing control measures remain an important way to reduce the burden of mosquito-borne disease.