Gates of the Underworld Structure Deck is a Structure Deck in the Yu-Gi-Oh! Trading Card Game (TCG). It is the twentieth deck in the TCG's Structure Deck series, following Lost Sanctuary Structure Deck. This deck is the TCG equivalent of Structure Deck: Devil's Gate in the OCG.

Each Gates of the Underworld Structure Deck contains 40 cards in total. The number of card of each rarity are as follows:

- 1 Ultra Rare

- 2 Super Rares

- 37 Commons