World history or global history as a field of historical study examines history from a global perspective. It emerged centuries ago; some leading practitioners have included Voltaire (1694–1778), Hegel (1770–1831), Karl Marx (1818–1883), Oswald Spengler (1880–1936), and Arnold J. Toynbee (1889–1975). The field became much more active (in terms of university teaching, textbooks, scholarly journals, and academic associations) in the late 20th century.

It is not to be confused with comparative history, which, like world history, deals with the history of multiple cultures and nations, but does not do so on a global scale. World historians use a thematic approach, with two major focal points: integration (how processes of world history have drawn people of the world together) and difference (how patterns of world history reveal the diversity of the human experience).

World history in the Western tradition is commonly divided into three parts, viz. ancient, medieval, and modern time. The division on ancient and medieval periods is less sharp or absent in the Arabic and Asian historiographies. A synoptic view of universal history led some scholars, beginning with Karl Jaspers, to distinguish the Axial Age synchronous to "classical antiquity" of the Western tradition. Jaspers also proposed a more universal periodization—prehistory, history and planetary history. All distinguished earlier periods belong to the second period (history) which is a relatively brief transitory phase between two much longer periods.

"World history is not a thing, but an activity, and various physical forms of expression such as lectures, books, journal papers and classroom lessons are criteria for it. An historian, for instance, may point to a book and say 'that's a world history', even if they cannot elucidate why. 'World history' should thus be defined through an examination of the various forms of expression taken as its criteria, not apart from or prior to them."

Jerry H. Bentley (2011) observed that "the term world history has never been a clear signifier with a stable referent", and that usage of the term overlaps with universal history, comparative history, global history, Big History, macro history, and transnational history, among others. Marnie Hughes-Warrington (2005) reasoned that "world history" is often mistaken to encompass the entire Earth, because works claiming to be "world histories" may have in practice a more limited scope, depending on the author's perspective: 'The "world" in world history (...) refers not to the earth in its entirety – both include and apart from human experience – but to the known and meaningful world of an individual or group.'

The advent of world history as a distinct academic field of study can be traced to the United States in the 1960s, but the pace quickened in the 1980s. A key step was the creation of the World History Association and graduate programs at a handful of American universities. Over the next decades scholarly publications, professional and academic organizations, and graduate programs in World History proliferated. World History has often displaced Western Civilization in the required curriculum of American high schools and universities, and is supported by new textbooks with a world history approach.

World history attempts to recognize and address two structures that have profoundly shaped professional history-writing:

Trying to escape the nation-state, global history tries to transcend nation boundaries by looking at larger unburdened by spacial limitations. Thus World History tends to study networks, connections, and systems that cross traditional boundaries of historical study like linguistic, cultural, and national borders. World History is often concerned to explore social dynamics that have led to large-scale changes in human society, such as industrialization and the spread of capitalism, and to analyse how large-scale changes like these have affected different parts of the world. Like other branches of history-writing in the second half of the twentieth century, World History has a scope far beyond historians' traditional focus on politics, wars, and diplomacy, taking in a panoply of subjects like gender history, social history, cultural history, and environmental history.