A managed IT service is an IT function provided to a customer by a third-party contractor. The provider takes on the responsibility of proactively monitoring and managing a customer's IT infrastructure — including hardware, software, and networks — to ensure optimal performance, security, and availability.

Managed IT services typically include ongoing support and maintenance, proactive monitoring, system administration, help desk support, and security management. Providers may also offer data backup and recovery, disaster recovery, network and server management, and cloud services.

The goal is to allow businesses to focus on their core competencies while outsourcing their IT needs to a reliable, experienced provider. This saves time and money while improving overall infrastructure and reducing the risk of downtime, data loss, and security breaches.