U.S. state flag consisting of a dark blue field (background) with the phrase “State of Oregon,” the date 1859, and an emblem in golden yellow on the obverse side; on the reverse is a representation of a beaver in golden yellow.

A number of U.S. state flags, based on the military colours of local militias, originally had different designs on the obverse and reverse, but the expense and complexity of their manufacture gradually led to their replacement by simpler banners. Oregon is now the only state with such a flag, just as Paraguay (Paraguay, flag of) is the only country to have a national flag with a different design on each side.

The Oregon state flag became official on February 26, 1925. In addition to the name of the state and the date of its admission to the Union (1859), the flag features elements from the state seal on the obverse side. The Pacific Ocean with ships, mountains, and symbols of agriculture, as well as a pioneer covered wagon and the phrase “The Union,” are represented. The 33 stars around the outside of the shield correspond to Oregon's order of admission to the Union. The beaver emblem on the reverse side recalls the importance of the animal to early trappers and hunters in the Pacific Northwest.