Rachael Ostovich (born February 25, 1991) is an American mixed martial artist who competes in the Flyweight division. A professional since 2014, she has competed in the UFC and Invicta Fighting Championships. After being released from the UFC, she made her debut for Bare Knuckle Fighting Championship in 2021.

Ostovich attended Moanalua High School and competed in cheerleading, judo, and wrestling. She began wrestling at 7 years of age, followed by cheerleading after seeing Bring It On, and judo in the off-season. She became team captain for all three sports in high school. Ostovich placed third at the 2008 HHSAA judo state championships, and placed first in 2009. She also placed first in the state for cheerleading, and third for wrestling.

Ostovich was a mixed martial arts (MMA) fan from childhood, citing her father Robert "Bob-O" Ostovich and Gina Carano as inspirations. Her father is a former professional fighter, trainer, and promoter. Her brother Robby is also a professional fighter. She trains out of her family's gym, Jesus Is Lord. Ostovich originally began training for MMA because she wanted to continue competing in sports after high school.

Ostovich began her amateur MMA career in 2010. Over the next three years, she compiled an amateur MMA record of 6–0, winning the 808 Battle Ground bantamweight championship, Destiny flyweight and bantamweight championships.

Ostovich made her professional MMA debut in January 2014 in her native Hawaii. She went 1–1 before joining Invicta Fighting Championships

Ostovich debuted for the all-female Invicta Fighting Championships in December 2014. She faced Evva Johnson at Invicta FC 10 and won the fight by split decision.

In her second bout for the promotion, Ostovich faced Andrea Lee on September 12, 2015, at Invicta FC 14. She lost the bout via verbal submission to an armbar in the third round.

In her third bout for the promotion, Ostovich faced Ariel Beck on May 7, 2016, at Invicta FC 17. She won the bout via a split decision.