Introduction: Children with anxiety disorders have been suggested to possess deficits in verbal fluency, shifting and attention, with inconsistent results regarding working memory and its subcomponents. This study extends previous findings by analyzing the performance of children with anxiety disorders in a wide range of neuropsychological functions. Methods: We evaluated 54 children with a primary diagnosis of an anxiety disorder according to diagnostic criteria from the Diagnostic and Statistical Manual of Mental Disorders, 5th edition (DSM-5) using subtests of a neuropsychological battery. The severity of anxiety disorders was assessed using the Pediatric Anxiety Rating Scale (PARS). We calculated the frequency of neuropsychological impairments (-1.5 standard deviation of the normative sample). Comparisons between groups were performed based on the severity of anxiety symptoms, as well as in the presence of one vs. more diagnoses of anxiety disorder. Results: We found higher impairment in visuospatial working memory (23.1%), semantic memory (27.8%), oral language (35.4%) and word writing (44.4%) in anxious children. Moreover, children with higher anxiety severity presented lower performance in visuospatial working memory, inferential processing, word reading, writing comprehension, copied writing, and semantic verbal fluency (d = 0.49 to 0.96 [Cohen’s d]). The higher the number of anxiety diagnoses, the lower the performance in episodic memory and oral and written language (d = 0.56 to 0.77). Conclusion: Our data suggested the presence of memory (visuospatial working memory and semantic memory) and language deficits (oral and writing) in some children with an anxiety disorder. Severity and number of anxiety diagnoses were associated with lower performance in memory and language domains in childhood.