Few interventions for Postnatal Depression (PND) have focused on parenting difficulties; the aim of this research was to investigate the feasibility and evaluate a parenting intervention (Baby Triple P) in women with PND. This was a pilot randomised controlled trial (RCT) to evaluate and determine the feasibility of the newly developed Baby Triple P compared with treatment as usual (TAU) in women with PND. In all, 27 female participants aged from 18 to 45 years (mean age = 28.4 years, standard deviation (SD) = 6.1), with a primary diagnosis of major depression and an infant under 12 months (mean age = 6.2 months, SD = 3.2 months), were recruited from primary care trusts in Greater Manchester, United Kingdom. Participants were randomly allocated to receive either eight Baby Triple P sessions in addition to TAU or TAU only. Outcomes were assessed at post-treatment (Time 2) and 3 months post-treatment (Time 3). Self-report outcomes were as follows: Beck Depression Inventory, Oxford Happiness Inventory, What Being the Parent of a New Baby is Like, Postpartum Bonding Questionnaire and the Brief Parenting Beliefs Scale-baby version. An assessor-rated observational measure of mother-infant interaction, the CARE Index and measure of intervention acceptability were also completed. Significant improvements from Time 1 to Time 2 and Time 1 to Time 3 were observed across both groups. Although women allocated to Baby Triple P showed more favourable improvements, the between-group differences were not significant. However, the intervention was highly acceptable to women with PND. A large-scale RCT is indicated.