Monopoly is a multi-player economics-themed board game. In the game, players roll two dice to move around the game board, buying and trading properties and developing them with houses and hotels. Players collect rent from their opponents and aim to drive them into bankruptcy. Money can also be gained or lost through Chance and Community Chest cards and tax squares. Players receive a stipend every time they pass "Go" and can end up in jail, from which they cannot move until they have met one of three conditions. House rules, hundreds of different editions, many spin-offs, and related media exist. Monopoly has become a part of international popular culture, having been licensed locally in more than 103 countries and printed in more than 37 languages. As of 2015, it was estimated that the game had sold 275 million copies worldwide.

Monopoly is derived from The Landlord's Game, created by Lizzie Magie in the United States in 1903 as a way to demonstrate that an economy that rewards individuals is better than one where monopolies hold all the wealth and to promote the economic theories of Henry George—in particular, his ideas about taxation. The Landlord's Game originally had two sets of rules, one with tax and another on which the current rules are mainly based. When Parker Brothers first published Monopoly in 1935, the game did not include the less capitalistic taxation rule, resulting in a more aggressive game. Parker Brothers were eventually absorbed into Hasbro in 1991. The game is named after the economic concept of a monopoly—the domination of a market by a single entity.