It stands for good til canceled order (good until canceled order); an order (placed to buy or sell securities) that remains on the books until it is either executed or cancelled (i.e., until another order to cancel is issued). It is an unfilled (working) order whose execution depends a specific requirement being met before it is otherwise cancelled. For example, a broker may be instructed by a client to buy or sell a security at a certain price whenever that price becomes available. It can be a limit/ stop order that has been placed but the price has not been available yet and therefore it is still not executed.

A good til canceled order (also known as an open order) may also refer to a market order that was placed during the closure hours of a market and has not filled yet.