Introduction: Hypertensive Disorders of Pregnancy are common and may result in increased maternal and neonatal morbidity and mortality. Multiple pregnancies confer an increased risk of development of a hypertensive disorder of pregnancy. The purpose of this study was to examine a large cohort of women delivering a multiple pregnancy in a single large tertiary unit, and to evaluate the implications of hypertensive disorders of pregnancy on both maternal and perinatal outcomes. Material and methods: Retrospective study of all twin pregnancies delivered at Cork University Maternity Hospital, Ireland over a 9-year period (2009–2017). The twin pregnancies were divided according to the presence or absence of hypertensive disorder of pregnancy and the two groups compared. Results: Maternal age >40 years, nulliparity, conception through use of a donor oocyte, and presence of obstetric cholestasis are all risk factors for the development of Hypertensive Disorders of Pregnancy in women with a multiple pregnancy. When a hypertensive disorder complicates a twin pregnancy, it increases the incidence of iatrogenic late prematurity & neonatal hypoglycaemia. Conclusions: This study is informative for clinicians caring for women with a multiple pregnancy with its relevant data on perinatal outcomes following a diagnosis of hypertensive disorder in pregnancy.