Plants vs. Zombies is a 2009 tower defense video game developed and originally published by PopCap Games for Microsoft Windows and OS X. The game involves a homeowner using a variety of different plants to prevent an army of zombies from entering their house and "eating their brains". It was first released on May 5, 2009, and made available on Steam on the same day. A version for iOS was released in February 2010, and an HD version for the iPad. An extended Xbox Live Arcade version introducing new gameplay modes and features was released on September 8, 2010. PopCap released a Nintendo DS version on January 18, 2011 with content unique to the platform. The PlayStation 3 version was released in February 2011 also with added new co-op and versus modes found in the Xbox 360 version. An Android version of the game was released on May 31, 2011 on the Amazon App Store, while it was also released to the Android Market (now Google Play) on December 14, 2011. On February 16, 2012, a version was released for BlackBerry PlayBook. Later a BlackBerry smartphone version of the game was released on January 2013 following the launch of BlackBerry 10. Furthermore, both the original Windows and Mac version of the game have been re-released with additional content in a Game of the Year version.

The game received a positive response from critics, and was nominated for multiple Interactive Achievement Awards, alongside receiving praise for its musical score. A sequel, called Plants vs. Zombies 2: It's About Time, was released on August 15, 2013 for iOS.

In Plants vs. Zombies, players place different types of plants and fungi, each with their own unique offensive or defensive capabilities, around a house in order to stop a horde of zombies from reaching the house of the residents. The playing field is divided into 5-6 horizontal lanes, and with rare exceptions, a zombie will only move towards the player's house along one lane (the main exception is if it has taken a bite out of a garlic). Planting costs "sun", which can be gathered for free (albeit slowly) during daytime levels and by planting certain plants or fungi. Most plants can only attack or defend against zombies in the lane they are planted in. In later levels, players can purchase upgrades with different offensive and defensive abilities.

The game uses several different level types and layouts. The game starts out in a front yard, and progresses to nighttime levels, where the gameplay is more challenging, with no replenishing sun unless specific plants are used, the backyard is visited, with a pool added, and the final levels are nighttime pool levels (where fog fills the right half of the screen except when specific plants are used), a lightning storm level in pitch black (except when illuminated by occasional flashes of lightning), and rooftop levels (on the final level, the player must face a huge robot operated by a zombie known as Dr. Zomboss). At set points throughout the game, the player is either warned through a letter by zombies or addressed by Crazy Dave to prepare for an ambush, where the game takes on a bowling style, using Wall-nuts to bowl down zombies, or a modified version of regular levels, where random plant types come up on a small selection, and the player can use the plants without spending sun. less