While The Underland Chronicles made Collins a well-known author, it paled in comparison to her next series in terms of ratcheting up her celebrity status. As Collins later recalled, The Hunger Games trilogy was born while she was watching television late one night. Flipping through the channels, Collins was suddenly struck by the lack of distinction between reality TV and coverage of the Iraq war.

In 2003, Collins published Gregor the Overlander, the first book of The Underland Chronicles.