The Royal Observatory was first established in Saint-Josse-ten-Noode in 1826 by King William I of the Netherlands under the impulse of Adolphe Quetelet.

It was home to a 100 cm (39 in) diameter aperture Zeiss reflector in the first half of the 20th century, one of the largest telescopes in the world at the time.

It now owns a variety of other astronomical instruments, such as astrographs, as well as a range of seismograph equipment (for detecting earthquakes).

Its main activities are reference systems and geodynamics, astrometry and dynamics of celestial bodies, astrophysics, and Solar physics.

Adolphe Quetelet first petitioned the government of the United Kingdom of the Netherlands to establish an astronomical observatory in Brussels in 1823.

Meteorological observations started early, but delivery and installation of astronomical equipment proceeded slowly.

After World War I the Central Bureau for Astronomical Telegrams was located in Uccle from 1920 to 1922 while it was headed by Lecointe.