3rd Avenue are two streets running north–south in Portland, Oregon, in the United States.
Burnside Street separates Northwest 3rd Avenue and Southwest 3rd Avenue on the west side of the Willamette River. The northern terminus of NW 3rd Avenue is at NW Hoyt Street, in the Old Town Chinatown neighborhood. The southern terminus of SW 3rd Avenue is south of downtown Portland, between SW Arthur and Meade Streets. Buildings and other sites along 3rd Avenue on the west side include the Lan Su Chinese Garden, Voodoo Doughnut, Cameron's Books and Magazines, the Plaza Blocks (Lowndsdale Square and Chapman Square), Terry Schrunk Plaza, and Keller Fountain Park.
On the east side of the river, there Burnside separates Northeast 3rd Avenue and Southeast 3rd Avenue. NE 3rd is separated into multiple sections, and there is a large cap around the Oregon Convention Center. NE Hancock Street serves as the avenue's northern terminus. SE 3rd Avenue turns into SE Division Street at its southern terminus.