Children’s privacy is put at risk through online sharing of location-based information. We study the effectiveness of an educational interactive comic on improving 11- to 13-year-old children’s privacy knowledge and behaviour immediately and one week after reading. Children’s privacy knowledge increased after reading either the comic or the text-only control, but the comic promoted superior knowledge retention a week later and was more successful at influencing children’s reported privacy behaviour than the control. Our 22 child-parent pairs found the comic facilitated learning for children, engaging, and easy to use. We discuss the implication on children’s short and long-term knowledge retention and behaviour, and the educational potential of comics at addressing the challenges of privacy and security education for children.