A social issue is a problem that affects many people within a society. It is a group of common problems in present-day society and ones that many people strive to solve. It is often the consequence of factors extending beyond an individual's control. Social issues are the source of conflicting opinions on the grounds of what is perceived as morally correct or incorrect personal life or interpersonal social life decisions. Social issues are distinguished from economic issues; however, some issues (such as immigration) have both social and economic aspects. Some issues do not fall into either category, such as warfare.

There can be disagreements about what social issues are worth solving, or which should take precedence. Different individuals and different societies have different perceptions. In Rights of Man and Common Sense, Thomas Paine addresses the individual's duty to "allow the same rights to others as we allow ourselves." The failure to do so causes the creation of a social issue.

There are a variety of methods people use to combat social issues. Some people vote for leaders in a democracy to advance their ideals. Outside the political process, people donate or share their time, money, energy, or other resources. This often takes the form of volunteering. Nonprofit organizations are often formed for the sole purpose of solving a social issue. Community organizing involves gathering people together for a common purpose.

A distinct but related meaning of the term "social issue" (used particularly in the United States) refers to topics of national political interest, over which the public is deeply divided and which are the subject of intense partisan advocacy, debate, and voting. In this case "social issue" does not necessarily refer to an ill to be solved, but rather a topic to be discussed.