An honesty box is a method of charging for a service such as admission or car parking, or for a product such as home-grown produce and flowers, which relies upon each visitor to pay at an unattended box using the honour system. Tickets are not issued and such sites are usually unmanned. When used in campgrounds and other park settings, they are sometimes referred to as an iron ranger as there is often an iron cash box instead of an actual park ranger. Some stores also use them for selling newspapers to avoid queues at a till.

Such boxes are typically used in rural areas where the either number of visitors/customers or the quantity and value of the products on offer is sufficiently low that a manned presence would not bring a positive return on investment. Many are also domestically-run operations where a manned presence is not feasible to carry out.