The purpose of this Special Issue “Nutrition in Inflammatory Bowel Disease (IBD)” is to increase knowledge regarding the role of dietary composition and effects in IBD, describing the prevalence of malnutrition in IBD and the effect on clinical outcomes, discussing methods of nutrition risk screening and assessment in IBD, and reviewing mechanisms through which diet and dietary components may affect disease severity. The articles focus on the following areas: Dietary Composition/Therapy Interventions in Ulcerative Colitis and effects on outcomes; Dietary Composition/Therapy Interventions in Crohn’s Disease and effects on outcomes; Nutrition Risk Screening and Assessment in IBD; Mechanisms of Diet in the pathogenesis of IBD.