The BP Pedestrian Bridge, or simply BP Bridge, is a girder footbridge in the Loop community area of Chicago, United States. It spans Columbus Drive to connect Maggie Daley Park (formerly, Daley Bicentennial Plaza) with Millennium Park, both parts of the larger Grant Park. Designed by Pritzker Prize-winning architect Frank Gehry and structurally engineered by Skidmore, Owings and Merrill, it opened along with the rest of Millennium Park on July 16, 2004. Gehry had been courted by the city to design the bridge and the neighboring Jay Pritzker Pavilion, and eventually agreed to do so after the Pritzker family funded the Pavilion.

Named for energy firm BP, which donated $5 million toward its construction, it is the first Gehry-designed bridge to have been completed. BP Bridge is described as snakelike because of its curving form. Designed to bear a heavy load without structural problems caused by its own weight, it has won awards for its use of sheet metal. The bridge is known for its aesthetics, and Gehry's style is seen in its biomorphic allusions and extensive sculptural use of stainless steel plates to express abstraction.

The pedestrian bridge serves as a noise barrier for traffic sounds from Columbus Drive. It is a connecting link between Millennium Park and destinations to the east, such as the nearby lakefront, other parts of Grant Park and a parking garage. BP Bridge uses a concealed box girder design with a concrete base, and its deck is covered by hardwood floor boards. It is designed without handrails, using stainless steel parapets instead. The total length is 935 feet (285 m), with a five percent slope on its inclined surfaces that makes it barrier free and accessible. Although the bridge is closed in winter because ice cannot be safely removed from its wooden walkway, it has received favorable reviews for its design and aesthetics.

Since the mid-19th century, Grant Park has been Chicago's "front yard", with Lake Michigan to the east and the Loop to the west. Columbus Drive runs north–south through Grant Park, with Daley Bicentennial Plaza in the northeast corner of the park. West of Columbus Drive, the northwest corner of the park had been Illinois Central rail yards and parking lots until 1997, when it became available for development by the city as Millennium Park. Millennium Park is also north of Monroe Street and the Art Institute, east of Michigan Avenue, and south of Randolph Street. For 2007, Millennium Park trailed only Navy Pier as a Chicago tourist attraction.

In February 1999, the city announced it was negotiating with Frank Gehry to design a proscenium arch and orchestra enclosure for a band shell in the new park, as well as a pedestrian bridge crossing Columbus Drive between Millennium Park and Daley Bicentennial Plaza. The city also sought donors to cover the cost of Gehry's work, which would eventually become Jay Pritzker Pavilion and the BP Pedestrian Bridge. At the time, the Chicago Tribune dubbed Gehry "the hottest architect in the universe" in reference to the acclaim for his Guggenheim Museum Bilbao. Millennium Park project manager Edward Uhlir said "Frank is just the cutting edge of the next century of architecture", and noted that no other architect was being sought. Gehry was approached several times by Skidmore, Owings & Merrill architect Adrian Smith on behalf of the city. In April 1999, the city announced that the Pritzker family had donated $15 million to fund Gehry's band shell and an additional nine donors committed a total of $10 million more to the park. That same day, Gehry agreed to the design request.

In November 1999, when he unveiled his initial plans for the bridge and band shell, Gehry admitted the bridge's design was underdeveloped because funding for it was not yet committed. Even at this early point, the need for a sound barrier for Columbus Drive traffic noise was recognized, although Gehry indicated this might take the form of a berm, or raised barrier. The need to fund a bridge to span the eight-lane Columbus Drive was evident, but some planning for the park was delayed in anticipation of details on the redesign of Soldier Field. In January 2000, the city announced plans to expand the park to include features that became Cloud Gate, Crown Fountain, the McDonald's Cycle Center, and the BP Pedestrian Bridge. Later that month, Gehry unveiled his next design, which depicted a winding bridge.

While the neighboring Jay Pritzker Pavilion changed relatively little from Gehry's 1999 design when built, the bridge went through several proposed designs. The proposal made in early 2000, which was expected to be executed in 2002, included a bridge that was a mere 170 feet (51.8 m) long and 20 feet (6.1 m) wide. That design was not approved, and Chicago Mayor Richard M. Daley's disapproval of Gehry's subsequent design of an 800–900-foot (240–270 m) bridge caused Gehry to come up with ten more designs. The first of these plans was for a Z-shaped bridge that would have run northwest–southeast with western ramps in Millennium Park, leading south, and eastern ramps in the empty north section of Daley Bicentennial Plaza, leading north. It would have required elevators to conform to the Americans with Disabilities Act. This plan was abandoned because it would have segregated the handicapped. Gehry had only designed two bridges previously, both in the mid-1990s (Pferdeturm USTRA Bridge in Hanover, Germany and Financial Times Millennium Bridge in London, United Kingdom) but neither was built.

The final design for the bridge was revealed in an exhibit at the Chicago Cultural Center on June 10, 2000. As designed and built, the bridge is 935 feet (285.0 m) long and 20 feet (6.1 m) wide, with a 14-foot-6-inch (4.42 m) Columbus Drive clearance. The clearance was designed to slightly exceed the 14-foot (4.3 m) standard set by the United States Department of Transportation's Federal Highway Administration for urban area interstate bridge clearances, and to allow for additional future layers of pavement below. This height is also greater than the maximum vehicle height of 13 feet 6 inches (4.1 m) set by the Illinois Vehicle Code. According to the Chicago Tribune the width of the "trenchlike" area spanned is approximately 150 feet (46 m), while The New York Times reports the bridge is over ten times longer than Columbus Drive is wide.