Objectives Gestational Diabetes Mellitus (GDM) affects hundreds of thousands of women each year. Many require medications to manage their blood glucose levels. Only insulin is approved by the U.S. Food and Drug Administration for use in pregnancy. While other medications can be used, their safety remains controversial. Few studies have examined women’s lived experience of using insulin for GDM. Our objective in this study was to foreground the voices of women speaking about their treatment experience. Methods We conducted two focus groups including 16 women treated for GDM with medications, primarily insulin. Topics included women’s experiences with GDM diagnosis and treatment including concerns about risks and benefits of treatments. Transcripts were analyzed using an inductive coding approach. Results Many women had negative experiences with insulin use, such as feeling that they had no voice in treatment decisions, and received inadequate information about insulin, including about the impact it would have on their daily lives. Many continued to have difficulty managing their blood sugar once on insulin, and they worried about the short term and long term health effects of insulin on themselves and their babies. They wanted more information about non-insulin treatment options as well as more social support. Conclusion In our sample of women with GDM, insulin treatment resulted in negative experiences with emotional and experiential impacts lasting beyond pregnancy. There is a need for more research on other medications for GDM, so that women can have access to more treatment options and better information to guide their choices.