The St. Johns Bridge is a steel suspension bridge that spans the Willamette River in Portland, Oregon, United States, between the Cathedral Park Neighborhood in North Portland and the Linnton and Northwest Industrial neighborhoods in Northwest Portland. It carries the U.S. Route 30 Bypass. It is the only suspension bridge in the Willamette Valley and one of three public highway suspension bridges in Oregon.

The bridge has a 1,207-foot (368 m) center span and a total length of 2,067 feet (630 m). It is the tallest bridge in Portland, with two 400-foot-tall (120 m) towers and a 205-foot (62 m) navigational clearance. The adjacent park and neighborhood of Cathedral Park are named after the Gothic Cathedral-like appearance of the bridge towers.

Designed by internationally renowned engineer David B. Steinman (1886–1960) and Holton D. Robinson, of New York, the St. Johns was the longest suspension-type bridge west of the Mississippi River at the time of construction. It is the only major highway suspension bridge in the Willamette Valley and one of only three major highway suspension bridges in Oregon.