Grand Uniform of the École Polytechnique

The history of the Grand Uniform of the École Polytechnique reflects numerous changes, modeled on the shifts in political regimes, successive governments, and wars that have shaped France's history since the late 18th century. From the National Convention to the Fifth Republic, the Grand Uniform reflects the evolution of societal organization.

Originally, polytechnic students were issued two uniforms: one for daily use, known as "BD" for Battle Dress in the 20th century, and the other, a ceremonial uniform called "grande tenue," which over time became known as the Grand Uniform. The interior uniform should not be confused with the "petite tenue" or Petit Uniforme, a formal dress similar to the Grand Uniform except for the headgear.

Although the interior uniform disappeared in the 20th century, the Grand Uniform has endured. Every student, called an "X," receives a Grand Uniform—commonly referred to as "GU," pronounced gy in polytechnic slang—which is worn for military ceremonies and specific events linked to the École Polytechnique, such as the Bal de l'X.

Since its creation in 1794, wearing the uniform has been a tradition that unites all generations of students who have passed through the École Polytechnique. It symbolizes belonging to a community that claims a heritage of over two centuries.