With the growing concern over children's safety online, understanding the effectiveness of parental mediation strategies through reliable questionnaires is crucial. This scoping review article examines the landscape of questionnaires designed to assess parental protection against children's problematic internet use, a critical area of research in the digital age. It aims to consolidate knowledge on developing, validating, and applying these questionnaires, identifying three key themes: theoretical foundations, validation processes, and real-world effectiveness. The review underscores the complexity of digital parenting, evidenced by the diverse theoretical frameworks that inform questionnaire development. It emphasises the importance of rigorous validation efforts to ensure these tools' reliability across various demographics, enabling a nuanced understanding of parental mediation strategies. Furthermore, the review demonstrates the practical utility of these questionnaires in enhancing children’s online safety, reflecting on their role in guiding research, interventions, and policy-making. In conclusion, this review emphasises the vital role of well-designed questionnaires in advancing research on parental protection strategies against children’s problematic internet use. It calls for ongoing efforts to refine these instruments to keep pace with the rapidly evolving digital environment, ensuring they remain relevant and effective in guiding interventions and policy-making to safeguard children’s online experiences. This work contributes to the academic understanding of digital parenting and offers practical insights for developing targeted, evidence-based approaches to enhance online safety for children.