This is a book review of Flags of the Night Sky: When Astronomy Meets National Pride by André Bordeleau. The book promises to "...catalogue every current national flag that has a link, no matter how tenuous, to astronomy and its objects." The astronomical information is fine, as would be expected from a published amateur astronomer and planetarium lecturer. I recommend the book to anyone with an interest, even a minor one, in vexillology. Of course, it is not intended as an introductory astronomy book, but I can imagine that it might spark an interest in some readers who might otherwise have no occasion to learn anything about astronomy.