Thea Queen is a fictional character from the television series Arrow, which is based on the DC Comics superhero Green Arrow. She is portrayed by actress Willa Holland and is the younger sister of the main character, Oliver Queen. Thea is known for her strong-willed personality and her journey from a troubled youth to a skilled fighter, eventually taking on the superhero identity of Speedy. Throughout the series, Thea faces various challenges, including family dynamics and personal struggles. Her character development includes training in combat and becoming a key ally to Oliver in his fight against crime in Star City. Thea's relationships with other characters, such as Roy Harper, also play a significant role in her storyline.