A campaign to raise the minimum legal sale age for tobacco products from 18 to 21 years known as Tobacco 21 is having a nationwide impact, with at least 200 localities in 14 states having already implemented a Tobacco 21 policy. A 2015 report from the Institute of Medicine (IOM) estimated the effects of such policy on cigarette use at the national level; however, little is known about the expected effects for individual states. The purpose of this study was to consider the effect on smoking initiation in Minnesota if the minimum sale age were 21 in 2015. Estimates from the Minnesota Adolescent Community Cohort and Minnesota Adult Tobacco Survey were used to calculate the uptake of smoking in a hypothetical cohort of Minnesota adolescents 15 to 20 years of age. Expected reductions in initiation in the IOM report were used to calculate the effects of Tobacco 21 policy on smoking uptake in this cohort. Results revealed that raising the sale age to 21 in 2015 would prevent 3,355 young Minnesotans from starting to smoke.