This chapter reviews and summarizes the primary literature on excessive gestational weight gain (GWG) interventions, including both randomized controlled trials (RCTs) and non-randomized interventions. It includes both categories of studies because many of the earliest and/or commonly cited interventions to limit excessive GWG were not RCTs. To be clinically meaningful, results of interventions must be relevant to specific patient populations in specific settings. Increasingly, obesity experts are suggesting that that a transdisciplinary and multilevel approach is essential for understanding and ultimately preventing obesity. Inclusion and exclusion criteria differed among the various studies. In general, studies that included physical activity as the primary intervention limited enrollment to women who had been sedentary. On the whole, the literature suggests that interventions to improve diet or physical activity during pregnancy or reduce excessive GWG have been moderately successful in doing so but the degree of restriction, if achieved, is generally modest.