Anxiety during pregnancy and the postpartum (perinatal) period is very common and is associated with adverse consequences for mothers and their infants. Currently, medication is the most commonly prescribed treatment for perinatal anxiety and the lack of nonmedication-based interventions for perinatal anxiety is a barrier to receiving effective treatment for many women. As such, the present single-blind, randomized controlled trial seeks to evaluate whether group-based cognitive behavioural therapy, the gold-standard psychological treatment for anxiety disorders in the general population, effectively treats perinatal anxiety symptoms when compared to a psychoeducation group, which is currently the most commonly prescribed non-medication-based treatment for perinatal distress.