O.J.V. the Koornbeurs is a youth association in Delft. The association was founded in 1912, has more than 200 members and is located in the national monument Koornbeurs on the Voldersgracht.

The Koornbeurs is an open youth association full of friendly members, more than half of which are TU Delft related. The rest of the members consist of HBO students, graduates and other Delft youth. The association aims to “contribute to the personal and social awareness of young people, to be a meeting point for young people, to promote a critical and active attitude towards society and to contribute to the fight against social injustice and for a better society.”

O.J.V. the Koornbeurs originated from the Delft branch of the national association Societas Studiosorum Reformatorum.

S.S.R. Delft was founded in 1907 and refounded in 1912. In 1940 the S.S.R.D. was finally recognized as a student association by the then called "Technische Hogeschool".

During World War II, the S.S.R.D. dissolved. Members of the S.S.R.D. were active in the resistance against the occupying forces. Twelve members were killed in the battle.

When the war ended, the municipality of Delft allowed the S.S.R.D. to use the basement of the Koornbeurs for events and assemblies.

Around the end of the 1950s, the association experienced a strong growth resulting in more and more activities opening up to non-members. This growth led to rumblings within the association in the early 1960s and disagreements about the foundation. Some especially wanted to focus on faith, while others saw more benefit in the social aspects of the association. The question of whether or not mixed dancing was allowed during parties was the straw that broke the camel's back. The part of the association that attached the most importance to the preservation of Christian identity split off in 1961 and founded C.S.R.-Delft.

In 1966 S.S.R.D. was a bubbling student association that burst out of the walls of the Koornbeurs society. On 26 and 27 October 1966, the national student cabaret festival Cameretten ’66 was organized on the occasion of the eleventh lustrum, which led to the creation of the national Cameretten festival. In addition to year clubs, S.S.R.D. had multiple sub-associations (theatre association Bubastis, music group Lyra, folkloric company Roísín Dubh, sports association Ariston) and 21 fraternities / diagonals (Donar, HET, Tartaros, Gladius, Dynamicos, Impeconi, Spartaca, Quartanda, Sjaleem, Chong, Elvirev, Obscura, OoDeeM, Pö, LAGro, Tenochtitlan, Malacandra, Nasikorn, Covenant, Quesada, Ontooson).

The freedom of the 1970s had a major impact on the association. There were calls to change the foundation of the association. The friction between the conservative and the progressive part became more and more intense.

In 1970 it was almost impossible to find a new board while there were almost 700 members. It was decided to dissolve the association. At the last minute a new board was found, supported by 250 members. As a result, the number of members was more than halved.

At the end of the 1970s it was included in the statutes that non-students could also become members and the dots disappeared from the abbreviation. The name was changed to Youth Association SSRD.

At the end of the eighties there were only 120 members, a low point in history.

Although the abbreviation SSRD was still used, the association increasingly profiled itself in the 1980s under the name of the building in which it was housed - the Koornbeurs. In 1991 the association permanently changed its name to Open Youth Association the Koornbeurs.