WNBA jump for the ball during game 5 of the 2017 WNBA Finals Sims was drafted second overall by the
Tulsa Shock in the
2014 WNBA draft. In her rookie season, Sims immediately entered the starting line-up for the Shock at the shooting guard position. Sims would instantly become a scoring sensation in the league; she scored a career-high 39 points in a 95–93 loss to the
San Antonio Stars. She finished her rookie season, averaging a career-high 16.7 points per game along with a career-high 4.2 assists per game in 34 games with 31 starts and was named to the
WNBA All-Rookie Team. The Shock finished in fifth place in the Western Conference with a 12–22 record, missing out on the playoffs. In 2015, Sims would have an injury-riddled season, as she missed 10 games with a knee injury. She finished the season with 23 games played along with 19 starts and averaged 16.0 points per game and 3.8 assists per game. The Shock would make the playoffs with the number 3 seed in the Western Conference, posting an 18–16 record, but were eliminated in a two-game sweep by the
Phoenix Mercury in the first round. In 2016, the Tulsa Shock relocated to
Dallas, Texas (which is approximately 15 miles away from Sims's hometown of
Irving) and were renamed the
Dallas Wings. In the 2016 season, Sims would be healthy; she played in 34 games with 30 starts and averaged 14.0 points per game along with 3.9 assists per game at shooting guard. The Wings missed out on playoff contention with an 11–23 record. In 2017, Sims was traded to the
Los Angeles Sparks, along with the number 11 overall pick in the 2017 WNBA draft, in exchange for two first-round picks in the 2017 WNBA Draft. She initially came off the bench, but would be inserted into the starting lineup at the shooting guard spot after
Essence Carson suffered a right elbow sprain. On August 24, 2017, Sims scored a season-high 28 points along with eight assists and six rebounds as a starter in an 82–67 victory over the Phoenix Mercury. The Sparks would finish with a 26–8 record as the number 2 seed in the league with a double-bye to the semi-finals, following last season's new playoff format. Heading into the playoffs, Sims remained the starting shooting guard for the Sparks. The Sparks would go on to advance to the Finals after defeating the Mercury in a three-game sweep of the semi-finals, making it Sims's first Finals appearance. Sims tied her playoff career-high of 22 points in Game 3, with the Sparks winning 89–87 to clinch their second consecutive berth to the Finals. However, the Sparks would lose in the Finals to the
Minnesota Lynx in five games. In February 2018, Sims re-signed with the Sparks in free agency. On May 20, 2018, in the Sparks' season opener, Sims scored a season-high 21 points in a 77–76 victory over the Minnesota Lynx. As the season went on, Sims would struggle and eventually would lose her starting position going into the playoffs. The Sparks finished as the number 6 seed in the league with a 19–15 record. In the first round elimination game, the Sparks defeated the Minnesota Lynx 75–68 to advance. In the second round elimination game, the Sparks would lose 96–64 to the Washington Mystics. In 2019, Sims again re-signed with the Sparks after they matched an offer sheet made by the Phoenix Mercury. On April 22, 2019, Sims was traded to the Minnesota Lynx in exchange for
Alexis Jones. Sims would be the starting point guard for the Lynx, her role enabled her to average a new career-high in assists. She would also end up being named an All-Star for the first time in her career after being voted into the
2019 WNBA All-Star Game and would make the
All-WNBA Second Team. The Lynx finished the season 18–16 with the number 7 seed, but were eliminated by the
Seattle Storm in the first round elimination game. In 2020, the season was delayed and shortened to 22 games in a bubble at
IMG Academy due to the
COVID-19 pandemic. Sims was suspended for the first two regular season games without pay stemming from a
DUI charge in October 2019 to which she pleaded guilty. She would end up missing more time after giving birth to her first child in April and eventually made her return in August. For the remainder of the team schedule, she started in 7 of the 13 games played, working her way back into the starting the lineup. The Lynx finished 14–8 with the number 4 seed, receiving a bye to the second round. In the second round elimination game, the Lynx edged out the
Phoenix Mercury 80–79, advancing the franchise back to the semi-finals. However, in the semi-finals, they would get swept by the
Seattle Storm who would end up being the eventual champions. Sims signed a one-year contract with the Atlanta Dream for the 2021 season on March 1, 2021. She appeared in 30 games for the Dream, averaging 25.1 minutes and 8.7 points per game. The team went 8-24, missing the playoffs. On May 3, 2022, Sims re-signed with the Minnesota Lynx on an undisclosed contract. On 13 May 2022, after the Lynx began the season 0–3, Sims left the team via "mutual separation" as one of six roster moves made by the team. On August 3, 2022, Sims signed a seven-day contract with the
Connecticut Sun. On June 6, 2023, Sims signed back with the
Dallas Wings on a hardship contract. Sims appeared in four games with the Wings before
Crystal Dangerfield was cleared to return for Dallas - forcing them to release Sims from her hardship contract. On June 28, 2023, Sims returned to Dallas on a standard (rest-of-season) contract for the Wings. Sims was not part of the Wings' training camp roster announced in April 2024. She played with Athletes Unlimited, serving as a team captain throughout their 2024 season, which was held in Dallas. Sims was signed to a hardship contract with the Wings on June 25, 2024. On August 17, 2024, Sims was signed to a hardship seven-day contract with the Los Angeles Sparks. On February 2, 2025, Sims re-signed with the Sparks. On July 2, she was waived by the Sparks. She averaged 9.8 points, 2.9 rebounds, and 3.5 assists in 12 games. On August 10, 2025 Sims signed with the Indiana Fever on a hardship contract due to the Fever's roster having several players out due to injury.
Overseas In the 2014–15 WNBA off-season, Sims played for
Bucheon KEB-Hana Bank in
South Korea. In the 2015–16 WNBA off-season, Sims played for
Abdullah Gül Üniversitesi B.K. in
Turkey. As of August 2016, Sims signed with
Botaş SK of the
Turkish League for the 2016–17 WNBA off-season. In 2017, Sims signed with
Adana ASKİ SK of the Turkish League for the 2017–18 WNBA off-season. In 2018, Sims signed with
Kayseri Basketbol of the Turkish League during the 2018–19 WNBA off-season.
Athletes Unlimited Sims has been a central figure in
Athletes Unlimited Pro Basketball since the league's inaugural season. She is the league's all-time leader in career leaderboard points, win points, stat points, and MVP points, and the only player to surpass 20,000 leaderboard points and 10,000 win points. Sims has recorded three consecutive medal finishes, including runner-up placements in 2024 and 2025, and was named to the AU All-Defensive Team in 2025, while also holding multiple league records for games played, captaincies, and Game MVP awards. In October 2025, Sims signed to return to
Athletes Unlimited Pro Basketball for its fifth season in Nashville, continuing her long-term involvement with the league. In March 2026, Sims became champion of the sixth season of AU Pro Basketball. ==National team career==