Tsuyu is a straightforward and laid-back individual who always says what's on her mind and what she thinks about others. Tsuyu prefers to be called "Tsu", but only by people she views as friends.[1] She commonly refers to everyone with the honorific "-chan", save for teachers and other authority figures.

Tsuyu has proven to be very observant about others, as she was the first to note the similarities between Izuku Midoriya and All Might’s Quirk. Tsuyu is noticeably calm and collected, being able to stay levelheaded in stressful situations. Smart and studious, Tsuyu is known for having great judgment and is rarely moved by emotion. Because of this, Recovery Girl describes her as a "perfect pillar of emotional support" capable of leading others.[2]However, even Tsuyu has limits when it comes to staying composed, having broken down in despair or heartbreak a few times. Her words may also come off as unintentionally harsh thanks to her blunt honesty, resulting in her feeling guilty and regretful when she speaks out against her friends.

Her usual expression consists of a vacant stare, which makes reading her thoughts and emotions difficult for those around her, creeping them out in the process. Tsuyu has a habit of tipping her finger against her mouth while speaking, pondering or showing curiosity. She also says "ribbit", emulating a frog's croaking, as a replacement for many of her single word replies.