A straw poll, straw vote, or straw ballot is an ad hoc or unofficial vote. It is used to show the popular opinion on a certain matter, and can be used to help politicians know the majority opinion and help them decide what to say in order to gain votes.

Straw polls provide dialogue among movements within large groups. Impromptu straw polls often are taken to see if there is enough support for an idea to devote more meeting time to it, and (when not a secret ballot) for the attendees to see who is on which side of a question. However, in meetings subject to Robert's Rules of Order, motions to take straw polls are not allowed.

Among political bodies, straw polls often are scheduled for events at which many people interested in the polling question can be expected to vote. Sometimes polls conducted without ordinary voting controls in place (i.e., on an honor system, such as in online polls) are also called "straw polls".

The idiom may allude to a straw (thin plant stalk) held up to see in what direction the wind blows, in this case, the wind of group opinion.