OBJECTIVE: This study aims to explore barriers to controlling gestational weight gain in pregnant Chinese women. DESIGN: Data were collected through semistructured interviews with pregnant women experiencing excessive gestational weight gain who struggled with weight management, and the data were examined using an interpretive content analysis. SETTINGS AND PARTICIPANTS: Fifty participants (≥18 years, with excessive gestational weight gain) were recruited when they visited the hospital for antenatal health checkups in Wuhan city (n=36) and Jinan city (n=14) between September and October 2018. RESULTS: Interpretive content analysis identified 75 barriers after examining diet, physical activity levels and general issues stemming from knowledge and beliefs, and physical, social, logistical, emotional and structural characteristics. Compared with reported deductive codes, this study inductively extracted 15 new codes. The most frequent codes showed that expectant grandparents greatly influenced pregnant women's lifestyles, through overprotection, traditional and conservative ideas and practices, and a lack of reliable knowledge or acceptable guidance on gestational weight control. CONCLUSIONS: This study provides a better understanding of the most important obstacles faced during decision making about gestational weight control in Chinese settings, especially the influence of traditional ideas/practices and expectant grandparents. Identifying the specific barriers to weight control should facilitate potential tailored supportive interventions. More efforts on health education for the whole family and a better use of maternal handbooks would be particularly beneficial.