Secondary insurance is a type of insurance that pays for some or all of the costs left after the primary insurer has paid. It is coverage that you can buy separately from a medical plan, and it helps cover you for care and services that your primary medical plan may not. Secondary insurance can be another medical plan, such as through your spouse, or a different type of plan you’ve purchased to extend your coverage, which is also called voluntary or supplemental coverage. Some types of secondary insurance include gap insurance, vision plan, dental plan, accidental injury plan, and hospital indemnity insurance. Secondary insurance can help pay out-of-pocket health care costs if you get seriously injured or sick. When you have multiple health insurance plans, the companies work together to determine which plan pays first and which one pays second. This process is called coordination of benefits, which dictates primary and secondary insurance. The primary and secondary insurer varies by type of health insurance, and your state and employer can also influence that process.