The objective of this study is to gain an in-depth understanding of issues related to gestational weight gain (GWG) including general health, diet, and physical activity among high and low income women and to elucidate socio-ecological and psychosocial risk factors that increase risk for excessive GWG. We conducted 9 focus groups with high (n = 4 groups) and low (n = 5 groups) income pregnant women aged 18-35 years to discuss health, GWG, diet and physical activity following a discussion guide. The constant comparative method was used to code focus group notes and to identify emergent themes. Themes were categorized within the integrative model of behavioral prediction. Low income women, in contrast to high income women, had higher BMIs, had more children, and were African American. Diet and physical activity behaviors reported by low income women were more likely to promote positive energy balance than were those of high income women. The underlying behavioral, efficacy, and normative beliefs described by both groups of women explained most of these behaviors. Experiencing multiple risk factors may lead to (1) engaging in several behavior changes during pregnancy unrelated to weight and (2) holding more weight gain-promoting beliefs than weight maintaining beliefs. These factors could inhibit diet and physical activity behaviors and/or behavior changes that promote energy balance and in combination, result in excessive GWG. Low income women experience multiple risk factors for excessive GWG and successful interventions to prevent excessive GWG and pregnancy related weight gain will need to recognize the complex web of influences.