An SLA is an agreement between a customer and service provider that defines the services to be provided and required service levels. An OLA is an internal agreement within a company that defines how groups will deliver services to support the SLA. While an SLA is a public commitment to customers, an OLA is an internal agreement on how groups will work together to ensure the SLA is met. OLAs form the foundation to enable the organization to fulfill its commitments in the SLA.