Gwen noticed that Sara Lance was making a move on her boyfriend when they were partnered for lab. Angered by this, she started severely bullying Sara along with her two friends at every opportunity, both inside and outside of school, which eventually escalated into physical assaults.
Several weeks later, the three of them chased Sara into a parking lot after school. Gwen knocked Sara down and pulled her hair, reiterating her warning for Sara to stay away from her boyfriend, whilst her friends stole Sara's belongings. The next day, Gwen had another encounter with Sara after school, in which she gave the latter a black eye.
Sometime afterwards, Gwen and her friends tried to corner Sara again as she was walking home. However, Sara and her sister, Laurel Lance, used their recent self-defense training to fend them off. As a result, Gwen finally ceased her bullying.