Anxiety and anxiety-related disorders are, as a group, the most common mental health conditions and are more common among women compared with among men. It is now evident that these disorders affect one in five pregnant and postpartum people and are more common than depression. For some disorders (e.g., obsessive–compulsive disorder), there is also evidence of an elevated risk for their development and exacerbation during perinatal periods. In this article, we review the literature pertaining to anxiety and anxiety-related disorders during the perinatal period. We also provide information related to pregnancy-specific anxiety and fear of childbirth constructs that exist outside of diagnostic classification but are particularly important in the perinatal context. We review the scope, prevalence, and etiology of these disorders as well as comorbidity, screening, assessment, and treatment. We conclude with an overview of some of the key gaps in knowledge and recommendations for future research.