A service-level agreement (SLA) in cloud services outlines the expectations and responsibilities between a service provider and its customers. It specifies key elements such as uptime, performance metrics, and support services. SLAs ensure that both parties have a clear understanding of what services will be delivered and under what conditions. This promotes accountability and helps in managing customer expectations. In case of non-compliance, SLAs often include penalty clauses, providing a framework for recourse. Overall, SLAs are crucial for ensuring service quality in the cloud environment.