The school got involved after former Perth College student Carrie Bickmore used her Gold Logie acceptance speech to talk about brain cancer.
Bickmore encouraged people to wear beanies for brain cancer and start a conversation about funding and research for the disease.
Year 8 students Keeley Sermon and Madeline Boyd decided to organise a fundraiser at the school after their parents watched the speech and encouraged them to get involved.
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READ NOW"We are aiming to raise awareness more than funding," Keeley said.
Madeline said she had lost a friend to brain cancer and one of Keeley's friends was diagnosed with brain cancer.
The girls spoke to the school assembly on Wednesday about how common the disease was and how people could help.
About half of the teachers and most of the students at Perth College wore beanies throughout the week.
Principal Jenny Ethel opted to wear a navy blue beanie, in keeping with the school's colour scheme.