The Sims 2 is a strategic life simulation game developed by Maxis and published by Electronic Arts. It is the sequel to the popular game The Sims.

Sims age through 6 unique stages: baby, toddler, child, teen, adult and elder (although another stage, 'young adult', was added with the University expansion pack). Unlike the previous game, when children stayed children and there was little game progress, the stages of life encourage players to move the game along and create relationships between Sims. Family relationships are much more integral to this version of the Sims than the previous version. As Sims age, get married and have children, these relationships are recorded in an extensive family tree.

In this installment of the series, Sims can have more realistic marriages with engagements and parties. Sims are pregnant before having children (unlike in the previous version, where children just appeared). Other unique events such as deaths, birthdays and a first kiss also take place in a Sim's lifetime. Good and bad experiences are kept as memories and can affect the Sim's behaviour.

The graphics and house design engines have improved with more choices for houses, neighborhood design, food and clothes. The Sims 2 Body Shop, a tool which allows a user to design a Sim's body, clothing, genetic features, etc., was available well before the game's release.

The Sims 2 introduces a new aspect into the game: Aspiration. Aspiration manifests itself in two ways: the aspiration which each Sim has, and the Aspiration Meter.

Sims will each have an aspiration which is set either when they are created by the player, generated by the game (if they are an NPC), or chosen by the player when they become a teenager. The five aspirations are: Romance, Family, Knowledge, Popularity and Fortune. A sixth aspiration, that of growing up, is possessed by all sims when they are toddlers and children, and a seventh aspiration, the Pleasure aspiration, was included with the Nightlife expansion pack. Also, an eight aspiration, the Grilled Cheese aspiration was included with the Nightlife expansion pack.

There are six levels to the aspiration meter: The highest is platinum, beneath that is gold, followed by two levels of green and two of red (red being negative aspiration and therefore an undesirable state). The level is raised when a Sim fulfills a "Want", and is lowered when a "Fear" is realized. Wants and Fears are different for each sim depending on several factors including aspiration type, age and aspiration meter level. They may change on a daily basis, and are displayed graphically in slot-machine fashion on the toolbar. When the Aspiration Meter is high, aspiration rewards may be properly used. For example, the Elixir of Life aspiration reward allows a Sim to live longer. If this aspiration reward is used before the Aspiration Meter reaches the gold level, however, it sometimes backfires and the Sim loses life days. The Aspiration Meter also affects how long an elder will live for once they enter this phase of their life.

This also means that while the game still has no set goals, there is a new strategic level to balancing a Sim's life as players now have a limited time in which to fulfill Aspirations, meet needs, progress in a career, socialize and possibly have a family.