The 2011 IIHF World U18 Championship Division I was an international under-18 ice hockey competition organised by the International Ice Hockey Federation.

Both Division I tournaments made up the second level of the 2011 IIHF World U18 Championships.

Latvia and Denmark won the Group A and B tournaments respectively and gained promotion to the Top Division of the 2012 IIHF World U18 Championships.

The Group A tournament was played in Riga, Latvia, from 11 to 17 April 2011.

The Group B tournament was played in Maribor, Slovenia, from 10 to 16 April 2011.