A casino is an establishment for gambling. Its customers gamble by playing games of chance or skill, with the house taking a percentage of all wagers made. Casinos are often built near or combined with hotels, resorts, restaurants, retail shops, and cruise ships. Some casinos also host live entertainment events such as stand-up comedy, concerts, or sports.

The most famous casino is in Monte Carlo, Monaco, which was established in 1863 and has long been a popular tourist destination. In the United States, Las Vegas is the largest casino market by revenue, followed by Atlantic City and Chicago.

Most modern casinos employ a variety of security measures to protect their patrons and property. These measures may include physical security forces and a specialized surveillance department that monitors all activity in the casino. Some casinos also employ a number of technological advances to prevent cheating or theft. For example, in table games, betting chips have built-in microcircuitry that interacts with a system to oversee the exact amounts wagered minute by minute; and roulette wheels are electronically monitored to discover any statistical deviations from expected results.

Because of the large sums of money handled within a casino, there is always the potential for employees and patrons to attempt to cheat or steal. This is often in collusion with one another or independently, and it can result in a number of different consequences, from minor to severe. As a result, casino security is generally highly regarded as an essential aspect of any casino operation.