Gillian Robertson is a Canadian mixed martial artist. She currently competes in the Flyweight division in the Ultimate Fighting Championship. 

Gillian holds the women’s UFC record for submissions at four. Robertson was born in Niagara Falls, Ontario, Canada. She started cardio kickboxing training at the age of 16 at American Top Team. She then joined MMA classes after a few months and started competing two years later. Robertson started her professional MMA career since 2016 after amassed a record of 9-1 in amateur fights. After fighting in five professional bouts she participated in The Ultimate Fighter 26 UFC TV mma competition series and was subsequently signed by the UFC after the show. 

In August 2017, it was announced that Robertson was one of the fighters featured on The Ultimate Fighter 26, UFC TV series, where the process to crown the UFC's inaugural 125-pound women's champion will take place. In the preliminary fights, Robertson faced Barb Honchak and lost the fight via TKO in the second round.

Robertson made her UFC debut on December 1, 2017 on The Ultimate Fighter 26 Finale against Emily Whitmire. She won the fight via a submission in round one. Her next fight came on May 27, 2018 at UFC Fight Night: Thompson vs. Till against Molly McCann. At the weigh-ins, McCann weighed in at 127 pounds, 1 pound over the flyweight non-title fight limit of 126. She was fined 20 percent of her purse, which went to Robertson. She won the fight via a rear-naked choke in round two. On September 22, 2018, Robertson faced Mayra Bueno Silva at UFC Fight Night: Santos vs. Anders. She lost the fight via a submission in round one. Robertson faced Veronica Macedo on February 23, 2019 at UFC Fight Night: Błachowicz vs. Santos. She won the fight via submission in the second round. Robertson faced Sarah Frota on July 27, 2019 at UFC 240. She won the fight via technical knockout in round two. Robertson faced Maycee Barber on October 18, 2019 at UFC on ESPN 6. She lost the fight via technical knockout in round one. Robertson was expected to face Taila Santos on June 20, 2020 at UFC Fight Night: Blaydes vs. Volkov. Due to undisclosed reasons, Robertson's opponent changed and she instead faced Cortney Casey. She won the fight via a rear-naked choke submission in round three.

Most wins in UFC women's flyweight division (four)

Most stoppage wins in UFC women's flyweight division (four)

Tied (with Roxanne Modafferi) for most fights in the UFC Women's Flyweight division history (six)