Underground Ernie is a Computer-animated children's television series produced by Joella Productions in the UK and shown by the BBC on both CBeebies and BBC Two. It is set in International Station, a fictional worldwide underground network, and focuses on the everyday adventures of Ernie, a friendly Underground supervisor, Millie, his multilingual colleague and Mr Rails the lovable maintenance man. The trains under Ernie's watchful eye all have characters of their own. There's Bakerloo, Victoria, Circle, Jubilee and the twins, Hammersmith & City. From time to time they are joined by their friends from across the world including, Paris, Brooklyn, Moscow, Sydney and Osaka.

The show is aimed at children between the ages of 3 and 8 years old. The initial series has 26 episodes each lasting 12-minutes. Its first showing on was on Monday 5 June 2006 on CBeebies.