The postpartum period is a particularly vulnerable time for the development of mental health concerns; postpartum depression (i.e. depression with onset between 0-12 months postpartum) affects approximately 13% of mothers in Canada. There are serious negative consequences to both mother and child during this period, yet only 20% of women seek treatment, citing significant systematic and personal barriers. Online support groups have been identified as a potential means of providing accessible mental health care during this time. Mother Matters is a 10-week online support group for women with postpartum depression and anxiety, run trained psychotherapists in the Reproductive Life Stages (RLS) program at Women's College Hospital in Toronto, Ontario. Mother Matters was designed to address barriers related to accessing postpartum mental health services: it can be accessed anywhere (online group), at any time (available 24/7), and with anonymity (to address the barrier of shame/stigma). The overall objective of the current pilot RCT is to determine the feasibility of conducting a large randomized controlled trial to evaluate the efficacy of the group, comparing outcomes among those with and without access to the program.