Overweight and obesity have a strong association with the development of hypertensive disorders of pregnancy. However, the mechanisms underpinning this relationship are not clear. Obesity is associated with insulin resistance, endothelial dysfunction, hypertension dyslipidaemia, inflammatory upregulation, alteration in immune function and prothrombotic changes. These changes may contribute to the development of hypertensive disorders of pregnancy, by influencing placentation, endothelial function, and inflammation. The genetic predisposition for hypertensive disorders of pregnancy needs to be examined in the context of obesity. Common antecedents such as dietary factors and inadequate physical activity might also explain the relationship between hypertensive disorders of pregnancy and obesity. This review is concluded with a synopsis and recommendations for further research.