The theory of demographic transition is a fundamental concept in development economics that explains the transformation of a country’s population structure over time as it undergoes economic and social development. This theory provides a framework for understanding the relationship between population growth, birth rates, death rates, and economic development. It was initially formulated based on the historical experience of Western European countries during the industrial revolution, where significant changes in mortality and fertility patterns were observed alongside economic growth, urbanization, and improvements in health and education. Demographic transition theory posits that societies move through distinct stages characterized by different combinations of birth and death rates, resulting in varying rates of population growth. The first stage is often referred to as the pre-transition stage, where both birth rates and death rates are high and roughly equal, leading to a stable and low population growth. High birth rates in this stage are usually associated with agrarian economies, where children are considered economic assets, providing labor and security in old age. High death rates result from poor nutrition, limited medical knowledge, inadequate sanitation, and frequent outbreaks of infectious diseases. As a result, the population remains relatively constant over long periods, despite high fertility, because high mortality offsets population increase. The second stage, known as the early transition stage, is characterized by a significant decline in death rates while birth rates remain high. This decline in mortality is often attributed to improvements in medical technology, better sanitation, clean water supply, increased food production, and public health interventions such as vaccinations. In this stage, societies experience rapid population growth because the gap between high birth rates and declining death rates creates a demographic surplus. Economic development during this stage may still be limited, but changes in living conditions and health infrastructure lead to reduced mortality. Countries in this stage often face challenges related to population pressure, such as demands on food, housing, and employment, which may necessitate policy interventions. The third stage, or late transition stage, occurs when birth rates begin to decline, following the earlier decline in death rates. Fertility reduction during this stage is influenced by various social and economic factors, including increased urbanization, rising income levels, higher female education and workforce participation, and widespread access to contraception. Parents begin to prefer smaller families due to the reduced economic necessity of having many children and increased investment in the quality of each child’s education and health. Population growth starts to decelerate as birth rates approach the lower mortality levels, creating a more balanced demographic structure. This stage is crucial for development economics as it highlights the interconnection between economic modernization, social change, and population stabilization. The fourth stage represents the post-transition period,