Zoonotic infections, which can develop into life-threatening conditions, should not be taken lightly. Despite the rising number of pet owners, knowledge of zoonotic diseases and children's behaviour when associating with pets at home remains limited. In Malaysia, few studies have investigated children's knowledge of zoonotic diseases and personal hygiene practices while caring for pets at home. Therefore, this focused on item development, validation, and analysis to assess content validity, acceptability, and contribution to internal consistency for age appropriateness among children. A pre-validation questionnaire was validated on two primary domains, knowledge, and behaviour, by subject matter experts (SME) specialising in zoonoses. A total of 66 children were selected to answer 14 dichotomous scale questions, with the responses subjected to further analysis. The post-validation process was performed by assessing the item suitability for the target group. Several items in the instrument should be modified. Meanwhile, some items should be retained due to the significance in evaluating the knowledge of disease transmission among children. The rationale underlying this modification stemmed from prior research findings and expert feedback. The final self-reporting instrument, Cognitive Affective Behaviours – Institute for Health Behavioural Research- Zoonoses Children-01 (CAB-IHBR-Zoonoses C-01), includes 10 items with adequate content coverage, acceptable qualities, and favourable expert reviews.