To sponsor something is to support an event, activity, person or organization by providing money or other resources in exchange for something, usually advertising or publicity.

Sponsorship may be an arrangement to exchange advertising for the responsibility of funding a popular event or entity. For example, a corporate entity may provide equipment for a famous athlete or sports team in exchange for brand recognition. The sponsor earns popularity this way while the sponsored can save a lot of money. This type of sponsorship is prominent in sports and television. Many companies want their logo on sponsored equipment in return.

People may sponsor an individual or group of people to undertake a fundraising task, usually for a charity or other cause requiring funding.

In 12 step parlance, a sponsor is one who takes a service commitment to help another to navigate the steps. Sponsors do not lead, nor push a sponsee but guide using their sobriety and their contact with their own higher power .

In the military, sponsor refers to weapons and equipment attached to the vehicles main chasis, (sponsor mounted,) as opposed to wings, pods, nacelles, or turrets. Many Fighting Aircraft and Tank Destroyers use sponsor mounts. The advantage is that heavier weapons can be equipped when this is done directly to the chasis, and the disadvantages being increased diffculty in aiming when compared with a turret, decreased fields of fire when compared with wings, (for fighters,) and access and heat dissipation difficulties when compared with any external mount.