An order (placed to buy or sell securities) that remains on the books until it is either executed or cancelled. 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.

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.

It is also known as good til canceled order (good til cancelled order).