Introduction: Twin gestations have greater nutritional demands than singleton gestations, yet dietary intakes of women with twin gestations have not been well described. Methods: In a prospective, multi-site US study of 148 women with dichorionic twin gestations (2012–2013), we examined longitudinal changes in diet across pregnancy. Women completed a food frequency questionnaire during each trimester of pregnancy. We examined changes in means of total energy and energy-adjusted dietary components using linear mixed effects models. Results: Mean energy intake (95% CI) across the three trimesters was 2010 kcal/day (1846, 2175), 2177 kcal/day (2005, 2349), 2253 kcal/day (2056, 2450), respectively (P = 0.01), whereas the Healthy Eating Index-2010 was 63.9 (62.1, 65.6), 64.5 (62.6, 66.3), 63.2 (61.1, 65.3), respectively (P = 0.53). Discussion: Women with twin gestations moderately increased total energy as pregnancy progressed, though dietary composition and quality remained unchanged. These findings highlight aspects of nutritional intake that may need to be improved among women carrying twins. Significance: What is Already Known about the Subject? Twin pregnancies have higher nutritional demands than singleton pregnancies. However, studies with longitudinal dietary data examining if, how, and at what points during gestation women may change their diets to support twin pregnancies have not been available. What this Study adds? Though total energy intake increased statistically significantly from the first to the third trimester, other aspects of diet remained stable across gestation. Similar to singleton pregnancies, diet quality was suboptimal among women pregnant with twins. [ABSTRACT FROM AUTHOR]