The flag of the city of Annandale, Virginia, was adopted on August 16, 2006.
The flag has a sky blue background, with a three white bars going inward from the outside of the flag, leading to a red oval. Inside the oval is a stylized light blue dogwood tree with a stylized red cardinal sitting on one of the tree's branches.
The flag of the city of Annandale was selected using one resident's design, and the Chamber of Commerce of the City of Annandale, Virginia, asked Peter Ansoff, president of the North American Vexillological Association (NAVA) and resident of Annandale, to suggest improvements to the design. Ansoff later created a panel of NAVA members, who suggested many improvements to the original design. Ansoff presented the Chamber of Commerce 27 new flag design variations, of which the city of Annandale voted on.