is an American former professional soccer player. She represented the United States national team on 160 occasions, winning two FIFA Women's World Cups and an Olympic gold medal. She spent most of her club career with National Women's Soccer League club NJ/NY Gotham FC. Known for her intensity, she played primarily as a wingback but played as a forward in college and occasionally played an attacking role in her professional career.

O'Hara was awarded the Hermann Trophy while playing for the Stanford Cardinal in 2009. She then played for FC Gold Pride and the Boston Breakers in Women's Professional Soccer. When the NWSL was formed in 2013, she joined Gotham FC (then known as Sky Blue FC). She later played for Utah Royals FC and the Washington Spirit, with whom she scored the winning goal in the NWSL Championship in 2021. She returned to Gotham and won her second NWSL Championship in 2023. She was named to the FIFA FIFPRO Women's World 11 in 2019.

O'Hara played internationally for the United States from 2010 to 2023. She appeared at four Women's World Cups in 2011; 2015, helping the team win the title; 2019, defending the title; and 2023. She appeared at three Olympic Games, including at the 2012 Olympics, where she was one of three U.S. players that played every minute of the tournament as they won gold; 2016; and 2020, where she won bronze.

O'Hara announced that she would retire from professional soccer at the end of the 2024 NWSL season. On September 21, 2024, she was put on the season-ending injury list due to chronic knee degeneration, thus effectively ending her career.