A mounting scientific literature demonstrates that weight stigma is a threat to physical and mental health. However, very little research has examined weight stigma in the context of pregnancy. This is surprising considering that weight gain is necessary for practically all healthy pregnancies. Moreover, a large percentage of women begin pregnancy already with a Body mass Index (BMI) in the overweight or obese range. This lack of attention is also concerning because weight stigma's known adverse effects on mental, physical, and behavioral health could be particularly detrimental to maternal health, both immediately and over time. Across two studies, this work aimed: (a) to document and describe the phenomenon of weight stigma during pregnancy and postpartum and (b) to investigate possible correlates and consequences of experiencing weight stigma during pregnancy and postpartum for mental, physical, and behavioral health. Results of the first study indicated that the majority of pregnant and postpartum women in the sample experienced weight stigma in some form, even those who began their pregnancies with a "normal weight" BMI. They experienced weight stigma from multiple sources, including immediate family, healthcare providers, and strangers, as well as from messages in the media and overarching sentiments or expectations from society in general. Additionally, experiences of weight stigma were cross-sectionally associated with negative consequences such as depression, maladaptive dieting behavior, emotional eating behavior, perceived stress, and postpartum weight retention. Results of the second study revealed that weight-related everyday discrimination was associated with more total gestational weight gain and medically defined excess gestational weight gain, in particular. Weight-related everyday discrimination was also associated with postpartum depressive symptomatology at one month postpartum, and prospectively predicted postpartum depressive symptomatology and postpartum weight retention at one year postpartum. Weight-related everyday discrimination was not, however, associated with physiological stress measures. These findings together provide proof-of-concept that pregnant and postpartum women do, in fact, experience weight stigma and that this stigma comes from multiple sources. Further, these weight stigmatizing experiences are implicated in unfavorable mental, physical, and behavioral health consequences for pregnant and postpartum women. Therefore, this work sets the foundation for future research to continue investigating weight stigma's connection to maternal health and to identify how to provide the best treatment possible for pregnant women.