Sider is visiting more than 80 schools, singing and speaking out against bullying. She performed at an assembly this week at John Burroughs Middle School.
It wasn't long ago that she had her own experience with kids who were mean.
"It was very, very hard for me, and I would come home crying almost every single day," she said.
But then her dad offered a bit of advice that stuck with her.
"Nobody has the power to ruin your day, and it was really a life changing thing for me," Sider said.
Sider wrote about overcoming her own bullying experiences in "Butterfly," a song about positivity and self-esteem. The feedback she's gotten has been the biggest reward.
"I like how she told her story and let other people tell what they've been through," said student A.J. Jackson. "I could really relate to her."
Wrist bands with her message "Nobody has the power to ruin your day" are given to all the kids at the assemblies to take home for inspiration.
Sider has been nominated for a Hollywood Music in Media award and will be performing at the ceremony next Thursday.