Siobhan Tilly
- Full Name: Siobhan Tilly
- Species: Human
- Gender: Female
- Mother: Adèle Tilly
- Husband: Iain Tilly
- Daughter: Sylvia Tilly
- Second daughter (DIS Novel: The Way to the Stars)
- By 2248: Elected Federation Councillor for United Earth (DIS Novel: The Way to the Stars)
- By position on the Federation Security Council