Underdevelopment, in the context of international development, reflects a broad condition or phenomena defined and critiqued by theorists in fields such as economics, development studies, and postcolonial studies. Used primarily to distinguish states along benchmarks concerning human development—such as macro-economic growth, health, education, and standards of living—an "underdeveloped" state is framed as the antithesis of a "developed", modern, or industrialized state. Popularized, dominant images of underdeveloped states include those that have less stable economies, less democratic political regimes, greater poverty, malnutrition, and poorer public health and education systems.

Underdevelopment per Walter Rodney is primarily made of two components, a comparative aspect as well the relationship of exploitation: namely, the exploitation of one country by another.^{[page needed]}

In critical development and postcolonial studies, the concepts of "development", "developed", and "underdevelopment" are often thought of to have origins in two periods: first, the colonial era, where colonial powers extracted labor and natural resources, and second (most often) in referring development as the postwar project of intervention on the so-called Third World. Mexican activist Gustavo Esteva asserted that underdevelopment began when American president Harry Truman delivered his inaugural address in 1949 since, after the second world war, poverty on a mass scale was suddenly "discovered" in these underdeveloped regions of the world. Esteva stated: "On that day two billion people became underdeveloped." More than half of the world's nations were categorized by what they lacked. The Euro-centric development discourse and its aura of expertise often conflated development with economic growth. When the world began to categorize nations based on their economic status, it narrowed the issue of underdevelopment to an economics problem. As a result, the solutions brought forth by development experts and practitioners were squarely economic—failing to address the profound political and social contexts such as colonial legacies and Cold War geopolitics.

The Green Revolution is a paradigm of a concerted effort of intervention in the name of global development. During this time, developed countries, in an attempt to modernize the global agricultural sector, sought to export the industrial agricultural model of production. At the start of the Green Revolution, the U.S., Canada, and other advanced European countries were giving their surplus crops to poorer countries in the form of food aid in order to mitigate widespread hunger that parts of the postcolonial world was then witnessing. Crops that weren't previously prevalent across the globe, such as wheat, were being transferred and from the global north to south in massive quantities. This occurred until developing countries, such as India, became heavily dependent on the food aid—much of which were crops that could not be grown locally. In order for dependent countries to keep receiving foreign assistance, the U.S. made it conditional for recipients of food-aid to adopt the whole industrial model of agriculture.

The revolution was titled "Green" not just because of its connections to agriculture but also was used as a tool to fight the "Red", or communist revolution. The West believed that hunger had the power to drive people to peasant revolutions, so food aid was used explicitly to fight the spread communism. While efforts were made to increase food security in poor nations by helping them move to being self-sufficient, the industrial model of agriculture that was exported to recipient countries had a complex system of necessary inputs. In order for yields to actually increase, farmers needed fertilizers, pesticides, and new irrigation systems, a costly chain of requirements that cut profits for the farmers even when their yields rose. The countries that were dependent on food aid now became dependent on the transnational corporations that provided agricultural inputs that the industrial model required. The Green Revolution was able to increase crop yields (at least in the short term, before land was degraded by the increased need for fertilizers and pesticides), but in the process it exacerbated vulnerable populations' poverty in countries that are now considered underdeveloped.

Several theories and types of explanation have been offered to explain why some countries have been underdeveloped and/or how their development may occur.

Seminal economist Adam Smith surmised not only that a nation's prosperity depends on free markets, but also that coastal geography - easy access to sea trade - plays an important part. Compared with Europe, large proportions of Africa, Asia and the Americas are far from the ocean. Jeffrey Sachs and his collaborators have demonstrated this relationship of geography with underdevelopment more systematically, pointing out that this relationship is also mediated by factors of agricultural productivity and disease prevalence.

Jared Diamond has proposed that continental alignment also played a part: the east–west alignment of Europe-Asia allowed diffusion of useful agricultural species, while the north–south alignments of the Americas and Africa inhibited such diffusion.