Seattle High School Memorial Stadium, commonly known simply as Memorial Stadium, was an outdoor athletic stadium in Seattle, Washington, located in the northeast corner of the Seattle Center grounds. It was used mostly for American football, soccer, ultimate frisbee, and concerts from 1947 to 2025. In its final configuration, the stadium had a seating capacity of 12,000.

The stadium opened in 1947 on the site of Seattle's former Civic Field, built as a memorial to the Seattle Public Schools pupils killed in the Second World War. A memorial wall listing the names of 762 students was dedicated in 1951. The stadium was built for Seattle School District high school sports, including the annual Metro League football championship, and continued to be used for Seattle school district competitions and adult recreational leagues until its closure in 2024. Several events at the Century 21 Exposition in 1962, including the world's fair opening ceremonies, were held at Memorial Stadium.

Memorial Stadium was also home to several professional sports teams, beginning with the Seattle Sounders of the North American Soccer League from 1974 to 1975. The seating capacity was temporarily expanded to 17,000 during the team's two-year stay at the stadium while waiting for the Kingdome to open. Similarly, an A-League reincarnation of the Sounders franchise played at Memorial Stadium, before moving to Seahawks Stadium in 2002. It was also the home stadium for Seattle Reign FC of the National Women's Soccer League from 2014 to 2018, as well as the Seattle Cascades of the Ultimate Frisbee Association (UFA).

The stadium was designed by Seattle architect George W. Stoddard, also known for his work on the Green Lake Aqua Theater and the south stands of Husky Stadium. The stadium opened on September 26, 1947, during a "jamboree" featuring eight of the city's high school football teams. Seattle High School Memorial Stadium was dedicated later that year in memory of the Seattle youth who gave their lives in World War II. A memorial wall at the east end is inscribed with the names of over 700 fallen individuals. The following year, the stadium hosted the first widespread local television broadcast in the Puget Sound region: the Turkey Day high school football game between West Seattle and Wenatchee, televised on November 25 by KRSC-TV (later KING-TV).

The stadium was the venue for much of the opening ceremonies for the Century 21 Exposition, a World's Fair held in Seattle in 1962. In 1967, it became the first high school stadium in the country to install artificial turf. After several sellouts for the Seattle Sounders in their inaugural North American Soccer League season, a set of temporary bleachers were installed in the stadium to increase capacity to 17,925 in 1975. For soccer matches, the pitch at Memorial Stadium was 110 yards (100 m) long and 60 yards (55 m) wide. The Sounders moved to the Kingdome at the end of the 1975 season after attempts to negotiate for a long-term lease and management of the stadium with the Seattle School District were unsuccessful.

In 1992, the scoreboard was replaced and the field was rededicated as "Leon H. Brigham Field", in tribute to the long-time high school football coach who pushed to build Memorial Stadium while serving as the Seattle School District's first director of athletics. The scoreboard was again replaced in 2018. Plans to replace the turf surface and widen the field area were also announced prior to a visit by Major League Soccer officials in 1994 to determine its suitability to host a Seattle team. Memorial Stadium was renovated in 1999, forcing the Sounders to move to Renton Memorial Stadium for one season.

The facility was not operated by the Seattle Center itself, but is owned by the Seattle School District and served as the "home field" for some high school football games played within the district. Memorial Stadium also hosted the first AAA (now 4A) state championship game for high school football in 1973, the first year of the state playoff system. The top-ranked Wenatchee Panthers were upset by the Kentridge Chargers, 26–24. Entering the title game, Wenatchee had given up just seven points all season and had been the top team in the state polls for four years. The stadium hosted the annual football championships for the Metro League, which were traditionally played on Thanksgiving Day.

As well as hosting two iterations of the Sounders franchise, Memorial Stadium served as home to several other pro and semi-pro sports teams. From 1967 to 1969 it was the home of the Seattle Rangers of the Continental Football League, a professional minor league. The Seattle Majestics, a women's American football team, played home games at Memorial Stadium from 2007 to 2009 before moving to French Field in nearby Kent. Seattle Reign FC of the National Women's Soccer League moved to the stadium in 2014 and played with a capacity limited to 6,000 for several seasons. They announced their move to Tacoma in January 2019 and then to Lumen Field in 2022. The American Ultimate Disc League's Seattle Cascades used the stadium for the majority of their home games from 2015 to 2025. In addition, the stadium hosted adult recreational league soccer and flag football.^{[citation needed]}