OBJECTIVE The long-term risk of end-stage kidney disease (ESKD) in type 2 diabetes is poorly described, as is the effect that younger age of diabetes onset has on this risk. Therefore, we aimed to estimate the effect of age of onset on the cumulative incidence of ESKD from onset of type 2 diabetes. RESEARCH DESIGN AND METHODS This study included 1,113,201 people with type 2 diabetes registered on the Australian National Diabetes Services Scheme (NDSS) followed from 2002 until 2013. The NDSS was linked to the Australia and New Zealand Dialysis and Transplant Registry and the Australian National Death Index. RESULTS Between 2002 and 2013, there were 7,592 incident cases of ESKD during 7,839,075 person-years of follow-up. In the first 10–15 years following the onset of diabetes, the incidence of ESKD was highest in those with an older age of onset of diabetes, whereas over longer durations of diabetes, the incidence of ESKD became higher in those with younger-onset diabetes. After 40 years of diabetes, the cumulative incidence of ESKD was 11.8% and 9.3% in those diagnosed with diabetes at ages 10–29 and 30–39 years, respectively. When death from ESKD without renal replacement therapy was included, the incidence of ESKD remained higher in older-onset diabetes for the initial 20 years, with no clear effect of age thereafter. CONCLUSIONS The long-term risk of ESKD in type 2 diabetes is high, which disproportionately affects those with younger onset of diabetes because they are more likely to survive to longer diabetes durations.