Background: Informant discrepancies between mother and child have challenged the assessment, classification, and treatment of childhood anxiety. Despite numerous studies on this matter, the implications and consequences for research and clinical practice remain unclear. Objective: The present study aimed to obtain meaningful clinical information about informant discrepancies by examining mother-child agreement for anxiety subtypes, and by exploring mother-child discrepancies in relation to independent observer ratings of behavioral anxiety. Method: The screen for child anxiety related emotional disorders was administered to 79 mothers and clinically referred anxious children aged 7-13 years. Mother-child dyads were observed during an anxiety-provoking task and independent observers rated children's observed anxiety. Results: The findings indicated a high level of mother-child disagreement on reports of anxiety. There was variability in levels of agreement between subtypes of anxiety, with significantly stronger mother-child agreement for separation compared to other forms of anxiety. Observed proximity between the mother and child was positively associated with child-reported separation anxiety and children's observed anxious voice was negatively associated with child-reported panic disorder. Conclusions: The results highlight the need to incorporate a multi-informant assessment of childhood anxiety in clinical practice and research, in particular for subtypes of anxiety problems that are characterized by less observable and more internally experienced components.