Objective: To review the effectiveness of physical activity (PA) and PA plus diet interventions in managing weight among overweight or obese (OW/OB) pregnant or postpartum women. Methods: Four databases were searched for randomized controlled studies published between January 2000 and December 2011 that reported weight change outcomes of PA interventions in OW/OB pregnant or postpartum women. PA alone as well as PA plus diet interventions were included. Results: Of 681 abstracts identified, 11 were included (7 trials with pregnant women and 4 trials with postpartum women). Overall, we found that PA interventions were effective for OW/OB pregnant as well as postpartum women. On average, pregnant women in the intervention groups gained 0.91. kg less (95% CI: - 1.76, - 0.06) compared with those in the usual care groups. Postpartum women in the intervention groups significantly lost more body weight (- 1.22. kg; 95% CI: - 1.89, - 0.56) than those in the control groups. In the subgroup analyses by PA intervention types, supervised PA plus diet interventions were the most effective. Conclusions: PA plus diet interventions may require more than advice; supervised PA programs or personalized prescription/goals are needed to prevent excessive weight gain for OW/OB pregnant women and excessive weight retention for OW/OB postpartum women.