Despite innovations in contraceptive methods, unintended pregnancies remain common. Researchers have examined psychological approaches to decrease unintended pregnancies through contraceptive use. Research findings on the effects of these psychological approaches show conflicting evidence. The aim of this meta-analysis was to clarify the impact of these psychological interventions on unintended pregnancies. Twenty-five randomised controlled trials (RCTs) with a total of 29,479 participants were analysed. Psychological interventions intended to increase the use of contraceptive methods were efficacious compared to control conditions, odds ratio for pregnancy in the intervention condition = 0.83. The results also showed that the longer an intervention’s follow-up period was, the less the prevention effect. Quality assessment of included studies indicated that all used a treatment manual and reported attrition. It also showed that most studies reported the reasons for drop-out and assessed the facilitator’s adherence to the intervention protocol. Altogether, these results support the efficacy of psychological interventions aimed at preventing unintended pregnancy thought contraceptive use.