Wendy is shown to be very desiring of wealth and prestige. She is usually a spoiled brat, and she even thinks of herself as Bowser's favorite child. She does whatever she can to impress her father and likes to be congratulated for her bad deeds. She is shown to have a very short temper over little things and can be violent when provoked. She is also known as strong-minded, and an intrusive tomboy. She seems to love water, as she is fought in regions that deal with water and has utilized underwater combat when fighting Mario.

Wendy is concise, thoughtful and studious regarding threats she hasn't encountered before. Wendy's tomboyish traits are because of her need to adapt to the fact that she's the only female among the Koopalings. She has a rivalry with Peach and Daisy.