Background and Objectives: To determine if executive functioning outcomes at school age are different for extremely preterm (EP; <28 weeks' gestation) or extremely low birth weight (ELBW; <1000 g birth weight) children born in 1991 to 1992, 1997, and 2005 relative to their term-born peers. Methods: Population-based cohorts of all EP/ELBW survivors born in the state of Victoria, Australia, in 1991 to 1992, 1997, and 2005, and contemporaneous controls (matched for expected date of birth, sex, mother's country of birth [English speaking or not], and health insurance status) were recruited at birth. At 7 to 8 years of age, parents of 613 children who were EP/ELBW and 564 children who were controls rated their children's executive functioning on the Behavior Rating Inventory of Executive Function (BRIEF). The proportion of children with elevated BRIEF scores (in the clinically significant range) in each birth group and era was compared by using logistic regression. Sensitivity analyses explored these associations after excluding children with intellectual impairment. Results: Across the eras, EP/ELBW children had higher rates of elevated scores than controls in almost all BRIEF domains. The 2005 EP/ELBW cohort had increased executive dysfunction compared with earlier cohorts, particularly in working memory and planning and organization. This effect persisted after accounting for demographic factors and weakened slightly when those with intellectual impairment were excluded. Conclusions: These results indicate a concerning trend of increasing executive dysfunction for EP/ELBW children who were born more recently. This may have adverse implications for other functional domains, such as academic achievement and social-emotional well-being.