Gestational diabetes mellitus (GDM) is a pregnancy complication that affects one in seven pregnancies. Emerging evidence demonstrates that children born of pregnancies complicated by GDM may be at increased risk of cardiovascular disease (CVD) in adulthood. Therefore, the aim of this study was to determine cardiovascular risk factors in offspring exposed to GDM in utero. PubMed, CINAHL, SCOPUS, and EMBASE databases were searched. Information was extracted on established CVD risk factors including blood pressure, lipids, blood glucose, fasting insulin, body mass index (BMI), and endothelial/microvascular function. The review protocol is registered in PROSPERO (CRD42018094983). Prospective and retrospective studies comparing offspring exposed to GDM compared to controls (non-GDM pregnancies) were considered. We included studies that defined GDM based on the International Association of Diabetes and Pregnancy Study Groups (IADPSG) definition, or prior definitions. The PRISMA guidelines were followed in conducting this systematic review. Methodological quality was assessed using the Newcastle–Ottawa Quality Assessment Scale. Study selection, data extraction, and quality assessment were done by two independent reviewers. The data were pooled using a random-effects model. Of 59 eligible studies, 24 were included in the meta-analysis. Offspring exposed to GDM had higher systolic blood pressure (mean difference (MD): 1.75 mmHg, 95% CI 0.57–2.94; eight studies, 7264 participants), BMI z-score (MD 0.11, 95% CI 0.02–0.20; nine studies, 8759 participants), and glucose (standard MD 0.43, 95% CI 0.08–0.77; 11 studies, 6423 participants) than control participants. In conclusion, offspring exposed to GDM have elevated systolic blood pressure, BMI, and glucose. Those exposed to GDM in utero may benefit from early childhood blood pressure measurements.