ObjectiveThis study aimed to evaluate the effect of a psychosocial education program on postnatal depression (PND), perceived stress, (PSS), and perceived maternal parenting self-efficacy (PMPSE). MethodsA randomized controlled trial design was used with stratified block randomization.The sample size consisted of 128 pregnant women. The women in the experimental group were provided with a psychosocial education program along with standard care, and the control group received standard care with an information pamphlet. Post-test assessments (PND, PSS, and PMPSE) were performed at 1 week, 6 weeks, and 12 weeks after delivery in both groups. ResultsThe result of the effect of the intervention on outcome variables on repeated measures ANOVA revealed that there was a positive statistically significant reduction in scores of postnatal depression [F (1, 119) = 18.832, p = 0 < 0.001] and perceived stress [F (1,119) = 22.488, p = < 0.001] and no statistically significant change in perceived maternal parenting self-efficacy in the experimental group [F (1,119) = 0.036, p = 0.850]. ConclusionThe psychosocial education program was found to be effective in reducing postnatal depression and stress related to pregnancy and childbirth to enable a smooth transition to motherhood. Practice implicationsGiven the benefits the program provides to women, this psychosocial education program could be incorporated into routine antenatal care for pregnant women.