Jane Turner is one of the Turner siblings living in 1980s rural England, alongside her older brother Sil and younger brother Robert. She possesses a stubborn and contrary disposition, frequently voicing opposition to the other children's ideas and wishes concerning the Psammead's magic, creating consistent friction during their decision-making.

Physically small and pudgy, her behavior aligns with traits of a "Tiny Tyrannical Girl." She exhibits bossiness and stubbornness, often resorting to loud tantrums when things don't go her way. These emotional outbursts pose a significant risk to the Psammead, as her tears are lethal to the creature, causing it considerable distress.

Her family relationships involve noticeable conflict. She engages in frequent arguments and sibling rivalry with Sil, the eldest brother. Sil occasionally bullies Robert, leaving Jane caught in the middle of their disputes. This dynamic contributes to her status as one of the primary "Butt Monkeys" of the series, experiencing wishes that backfire comically or problematically.

Despite her difficult personality, moments reveal a caring side, particularly towards family. When her grandmother falls ill, concern motivates Jane to wish for transportation to the Blue Coast for the day. This requires her and the Psammead to covertly assume her grandmother's responsibilities to hide the elderly woman's absence, demonstrating initiative for family well-being, albeit with complicated consequences.