Uncloud is information technology (IT) industry slang for the removal of applications and data from a cloud computing platform. An uncloud initiative may also be referred to as a decloud initiative or a reverse cloud migration. 

During a software-as-a-service (SaaS) uncloud project, the cloud customer, or channel partner acting on its behalf, will work with the cloud provider to extract the customer's applications and related data. Although pushing the customer's applications and data up to the cloud may have taken very little time initially, declouding may take longer than expected, especially if the cloud vendor is a public cloud provider. The task involves mapping the application's dependencies within the cloud vendor's infrastructure and locating all instances of the customer's data. In some cases, the customer may have to wait for the cloud vendor's scheduled downtime in order to move applications and data. In other cases, the cloud vendor may limit the customer's use of migration tools so as not to negatively affect application performance for other customers in the provider's multi-tenant architecture.

Customers cite a number of reasons for wanting to uncloud, including concerns related to cost, compliance, security, data sovereignty and difficulty integrating cloud-based applications with on-premises business intelligence (BI) applications and data. Anecdotal evidence suggests that customers who move back from the cloud often choose to implement a converged infrastructure, managed in-house.