Monopoly on Nintendo DS: No Official Release, But Alternatives Exist

There is no official Monopoly game released for the Nintendo DS.

Closest Official Alternatives on DS

• Monopoly City (2009, DS/Wii): City-building spin-off; bid on districts, build 3D buildings, no classic board.
• Mario Party DS (2007): Board-game-style party game with minigames — captures the "roll & move + compete" vibe with Nintendo characters.
• Fortune Street / Boom Street (Wii/3DS): Monopoly-meets-Mario Party with stocks; no DS version.

Unofficial / Homebrew

• Fan-made Monopoly ports exist on DS homebrew scenes (DSi/3DS custom firmware). Not endorsed by Hasbro/Nintendo; legal gray area.
• Web-based Monopoly clones playable in DS browser (very slow) or via DSiWare homebrew.

Modern Portable Monopoly

• Monopoly (Switch / PS4 / Xbox / PC / Mobile) — full classic + house rules + online.
• Monopoly GO! (iOS/Android) — free-to-play, mobile-first, very popular.

If you must play on DS hardware, Mario Party DS is the superior board-game experience.