Vietnam’s population hit the 100 million milestone. Where’s it headed?

The population of Vietnam reached the 100 million mark in 2023. Fifty years ago, in 1976, when it was reunified as the Socialist Republic of Vietnam, the country had fewer than half as many inhabitants (46 million). A hundred years ago, it had only one sixth as many (16 million) (Figure 1). When we compare the current demographics to other Asian countries, we can identify patterns specific to Vietnam.

Its population is likely to continue growing and could reach a peak of 110 million by the mid-21st century, according to the United Nations’ medium population projections. These projections anticipate that the population may then shrink back down to 92 million by the year 2100. They assume that fertility, estimated at an average of 1.9 children per woman in 2023, will decline to 1.7 children per woman by 2100.

How has the population of Vietnam reached 100 million? Why is it likely that growth will soon stop? What will the country’s population look like in the future?

Growth is linked to the demographic transition

The significant increase in Vietnam’s population during the 20th and early 21st century is linked to the country’s demographic transition. Like everywhere in the world, mortality has fallen, particularly child mortality, leading to an excess of births over deaths that has fuelled population growth. The pace of growth reached a high of over 3% per year in the mid-1950s and has since slowed year on year, primarily due to falling fertility.

In 2023, the average number of babies born to Vietnamese women is 1.9, as previously mentioned; this figure was around 6 in the 1960s and early 1970s. Figure 2 (below) allows for a comparison of fertility trends in Vietnam with those in three other East and Southeast Asian countries: China, South Korea, and Thailand.

Vietnam’s one- or two-child policy

Eighty years ago, concerned about rapid population growth, the authorities in North Vietnam implemented a policy to limit births. In 1963, the government first limited families to three children, establishing two or three children each spaced 5 to 6 years apart as the norm.

The policy then became more restrictive in 1988, with the rule changing to one or two children per couple. It applied to families living in towns or in densely populated areas (industrial zones, rural regions of the Red River and Mekong Deltas, and the coastal plain provinces).

On the other hand, the policy was less strict towards ethnic minorities from poor, isolated, and sparsely populated regions, who were permitted to have three children.

Did birth control policy have an impact?

Did Vietnam’s birth limitation policy cause its decline in fertility? This question can be posed to all countries in the Global South, particularly in Asia, where governments have tried to limit births when the population was growing rapidly and where fertility has significantly declined. It is the case in South Korea, China, and Thailand, where the decline happened earlier and more rapidly than in Vietnam, with fertility rates reaching even lower levels in 2023, respectively, 0.7, 1.0, and 1.2 children per woman (Figure 2).

The Chinese government, for example, started trying to limit births from the mid-1950s, but the policy was not confirmed until the 1970s and was subsequently made more restrictive, notably in 1979 with the one-child policy.

In Thailand, fertility fell at the same time as in China and equally rapidly. But instead of being coercive, its policy since the 1970s has consisted of incentives, such as the liberalisation of abortions and sterilisation, as well as financial support for schooling and household farming for couples having a maximum of two children. The rapid fall in fertility occurred in South Korea several years earlier, accompanied by measures aimed at promoting contraception and sterilisation, but also without coercive measures.

Vietnam’s birth limitation policy ended up somewhere between that of China’s coercive one and those of South Korea and Thailand, both of which used incentivising measures.

The actual impact of these policies, however, is difficult to measure. While fertility fell equally rapidly in the 1970s and 1980s in China and Thailand, this was primarily because families in these countries wanted fewer children at that time—just as in other countries during periods of improved education and living conditions.

Changing course: When the State seeks to boost the birth rate

Concerned about its rapidly ageing population (see the population pyramids in Figure 3), the Vietnamese government gradually relaxed the one- or two-child policy in the late 2010s before completely abandoning it in 2025 to advocate two-child families. As in other areas, Vietnam followed China’s example with this policy reversal, the latter having abolished its one-child policy in 2015. China subsequently implemented the “three-child policy” in 2021, apparently to no effect so far, as Chinese fertility has never been lower.

Sex selection

Generally speaking, 105 boys are born for every 100 girls. In Vietnam, the proportion of male newborns has increased since the 2000s, with the male-to-female birth ratio reaching 114 boys per 100 girls in the second half of the 2010s (Figure 4). A similar increase had been observed 20 years previously in South Korea and China, precursors in this respect.

The increase is explained by a strong desire in these countries to have at least one boy and by couples’ selective abortion of girls to achieve this. More precisely, the phenomenon results from the convergence of three factors: reduced family size, desire for a son at any costs, and the broad availability of ultrasound scans.

However, this pattern is not observed in all Asian countries: Thailand is a notable exception. In India, it is only observed in the north of the country. Likewise, in Vietnam, the north is more affected than the south, with a particularly high male-to-female birth ratio seen in the Red River Delta and the mountainous regions of the north (Figure 5).

This north–south divide is linked to cultural differences. The Red River Delta, in the north, was occupied by China for more than a thousand years and is the region of Vietnam most heavily influenced by Chinese culture and Confucian traditions.

In regions like this, boys are often preferred because they bear responsibility for continuing the family lineage and fulfilling the obligation of filial piety manifested through the worship of ancestors. The Mekong Delta in the south, on the other hand, was for several centuries part of the Khmer Empire and is culturally similar to Cambodia and Thailand.

What are the consequences for generations with a significant male surplus?

The imbalance in the sex ratio at birth has been decreasing for several years and it may ultimately return to its normal level, as it has in South Korea. However, generations of Vietnamese children with a significant surplus of boys have already been born. These generations are likely to experience the consequences of this imbalance throughout their lives, particularly when they are old enough to start looking for a long-term partner: girls, in the minority, will have no trouble finding a partner, whereas some boys may find themselves without one.

Population projections need to take the phenomena into account: the first generations affected, those born in the mid-2000s, are now old enough to have children; women, of whom there are fewer, will give birth to fewer children in total, not enough to replace their generation.

For a ratio of 105 boys per 100 girls, each woman needs to bear 2.1 children to ensure replacement. For a ratio of 113 boys per 100 girls, as in the second half of the 2010s, this figure needs to be 2.2. Population growth in Vietnam could slow down even more quickly than the fertility decline would suggest. Population ageing would then occur more rapidly, as is already the case in South Korea and China, where sex selection began 20 years earlier than in Vietnam.

Will fertility in Vietnam follow the same pattern as that of its neighbours? After declining from the 1970s to the 1990s, the total fertility rate seems to have stabilised at around two children per woman since 2000. Will it remain at this level or fall to even lower levels, as it has already done in the two major regions of the South (Southeast and Mekong Delta) and as in South Korea, China, and Thailand?

These countries have thus far led the way for Vietnam in terms of fertility trends. Vietnam’s fertility rate could fall even further over the coming years if it continues to follow the example of its neighbours.

Gilles Pison received funding from the French National Research Agency and the National Institutes of Health (NIH) the United States federal government.

Catherine Scornet ne travaille pas, ne conseille pas, ne possède pas de parts, ne reçoit pas de fonds d'une organisation qui pourrait tirer profit de cet article, et n'a déclaré aucune autre affiliation que son organisme de recherche.