|Role||, Full Sister, Wealthy|
|Visual novels||Side character - Hana yori Dango -Koi Seyo Otome!-|
|Voiced by||Nabatame Hitomi|
Tsubaki is Tsukasa's sister. She is four years older than Tsukasa. When she and Tsukasa were little, she cared for Tsukasa and tried to teach him to not act naughty because their parents were always overseas. When she was a student in Eitoku, she did some modelling in Paris, which made her an idol at Eitoku. After she graduated from Eitoku, she dated a man of common wealth, which led to her mother forcing them apart so that Tsubaki could marry a wealthier man. She is one of the few people who is not afraid to stand up to her brother, a trait that Tsukasa secretly admires in her.