Belgium’s population rises to 11.87 million as migration drives growth and ageing accelerates

Belgium‘s population reached 11,867,634 on 1 January 2026, according to new figures from the Belgian statistics office, Statbel, aka Statistics Belgium. The country gained 42,083 residents during 2025, representing population growth of 0.36%.

While the population continued to increase, the pace of growth was relatively modest compared with recent years. The latest figures highlight two major demographic trends shaping Belgium: a growing reliance on international migration for population growth and the continued ageing of the population.

Migration offsets natural population decline

Belgium recorded more deaths than births for the fourth consecutive year in 2025, resulting in a negative natural balance of 4,890 people.

Demographers attribute this trend largely to population ageing. As the share of older residents increases, deaths naturally rise because older age groups face higher mortality risks. At the same time, the proportion of younger generations is shrinking, reducing the number of women of childbearing age. Combined with declining fertility rates, this has kept birth numbers low.

Population growth was therefore entirely dependent on migration. Belgium recorded a positive international migration balance of 47,562 people during 2025, meaning more people moved into the country than left it.

Although still substantial, international migration was lower than during the period between 2021 and 2024, when migration flows were exceptionally high. Those years were influenced first by a post-pandemic rebound in international mobility and later by geopolitical developments, particularly the war in Ukraine.

Flanders grows fastest

The Flemish Region recorded the strongest population growth among Belgium’s regions, gaining 33,584 residents, an increase of 0.49%.

Like the rest of the country, Flanders experienced a negative natural balance, with deaths exceeding births by 4,176 people. However, this was more than compensated for by positive international migration (+24,319) and internal migration from other Belgian regions (+13,736).

The Walloon Region grew by 8,460 residents, or 0.23%. It also recorded a negative natural balance (-5,817), but benefited from both international migration (+9,255) and internal migration (+4,817).

By contrast, the Brussels-Capital Region remained virtually unchanged. The region gained only 39 residents during 2025.

Brussels was the only Belgian region to maintain a positive natural balance (+5,103), reflecting its younger population profile. It also recorded strong international migration (+13,988). However, these gains were almost entirely offset by a large negative internal migration balance (-18,553), as more residents moved from Brussels to other parts of Belgium than vice versa.

One in five Belgians is now over 65

The figures also reveal the continued ageing of Belgian society.

On 1 January 2026, 20.67% of Belgium’s population was aged 65 or older, meaning more than one in five residents had reached retirement age. Thirty years earlier, in 1996, that figure stood at 16.03%.

The pressure on the working-age population has also increased significantly. In 1996 there were 26.73 people aged 65 or over for every 100 residents aged between 20 and 64. By 2026 that figure had risen to 35.94.

Older age groups themselves are also ageing. Nearly one-third of all Belgians aged 65 and above are now at least 80 years old. People aged 80 and over account for 5.69% of the total population, compared with 3.81% in 1996.

Statbel’s long-term demographic analysis shows the country’s population pyramid gradually shifting upwards as the post-war baby boom generation grows older. The largest age groups have moved from people aged 30 to 49 in 1996 to those aged 60 to 79 in 2026.

Regional differences in ageing

Population ageing is not occurring evenly across Belgium.

The Flemish Region has the oldest population profile. Residents aged 65 and over account for 22.06% of the population, while 6.35% are aged 80 or older.

In the Walloon Region, 20.57% of residents are aged 65 or above, with 5.13% aged 80 and over.

Brussels stands apart. Only 13.36% of residents are aged 65 or older, and 3.73% are aged 80 or over. Unlike the other regions, Brussels has seen the share of elderly residents decline since the mid-1990s, reflecting its younger and more internationally mobile population.

Fewer residents born in Belgium

Another long-term trend highlighted by the figures is the declining share of residents who were born in Belgium.

In 1996, 90.16% of the population had been born in Belgium. By 2026 that proportion had fallen to 79.80%.

Regional differences are particularly striking. Around eight in ten residents in both Flanders and Wallonia were born in Belgium in 2026, at 83.36% and 83.06% respectively.

In Brussels, however, only 50.57% of residents were born in Belgium, meaning almost half of the capital’s population was born abroad.

Over the past three decades, Brussels has experienced the most pronounced change. The share of residents born in Belgium fell by more than 21 percentage points between 1996 and 2026, compared with declines of almost 11 percentage points in Flanders and just over 5 percentage points in Wallonia.

Demographic challenges ahead

The latest figures underline how Belgium’s demographic growth increasingly depends on migration rather than natural population growth. At the same time, an ageing population is placing growing pressure on the country’s working-age population and social systems.

With deaths continuing to outnumber births and the share of older residents steadily increasing, migration is expected to remain a key factor shaping Belgium’s demographic future in the coming decades.