ESSEC Business School (École Supérieure des Sciences Economiques et Commerciales) is a French business school and grande école. Its main campus is located in Cergy. ESSEC also operates campuses in Paris, Rabat, Morocco, and Singapore.

Established by Jesuits in 1907, ESSEC was created as a response to the opening of HEC Paris. It operated independently until 1981, when it came under the governance of the Versailles Chamber of Commerce, which later became part of the Chamber of Commerce and Industry of Paris Île-de-France in 2013. ESSEC is currently a member of the CY Alliance (formerly Université Paris-Seine), a group of academic institutions in the Paris region.

ESSEC was founded in 1907 under the Economic Institute by Ferdinand Le Pelletier in Paris. Its creation followed the movement of other private business schools established under Catholic guardianship in the early 20th Century, such as HEC Nord (which later became EDHEC) by the Catholic Institute of Lille and ESSCA by the Catholic Institute of Angers.

The establishment of the Falloux Laws in 1854 allowed the development of religious secondary education. Following the Dreyfus affair (1895) and the law of separation of church and state (1905), the Church sought to regain influence, in particular by disseminating its moral values in the economic sphere and by training a new generation of business leaders. ESSEC became the Catholic Church's response to the creation of HEC, in the context of the struggle of religious congregations, especially between Jesuits and the secular and republican ideology of the state. The stated aim of the new institution was to “train leaders for a commercial and economic career, which requires competent men, imbued with Christian and human values”. The school was located at the École Sainte Geneviève (created by Jesuits in 1854) in the Latin Quarter. The first class had seven students, and studies lasted two years; in 1909, an optional third year was introduced.

The original course was structured around general subjects including law, accounting, languages, and techniques. With the introduction of Christian moral values, students attended a weekly apologetics conference in the chapel of the École Sainte Geneviève. Scientific education (physics, chemistry, and factory visits) complemented technical education (calligraphy, shorthand, and drafting of commercial documents).

Following the 1905 law on the separation of church and state, the school's premises were confiscated in 1913, and ESSEC was absorbed into the Catholic Institute of Paris (ICP). As a consequence, the school's resources were significantly reduced; for example, it had only one amphitheatre borrowed from ICP, and the elementary section was removed. During this period, the curriculum included languages, history of trade, commercial geography, political economy, law, and accounting, with a strong emphasis on languages totalling ten hours per week.

The school struggled during the First World War. In 1914, it had only four first‑year students and two second‑year students and was temporarily closed before reopening in 1915. The optional third year was dropped, and the school did not regain financial stability until 1920, when more than 50 students enrolled in the first year. In 1923, the Students’ Association was created with a solidarity fund for war widows and orphans. In 1926, the first alumni directory was published, and three years later, the first courses in business ethics were introduced. By 1930, enrollment had increased to 150.

During the Great Depression in the 1930s, ESSEC reduced tuition fees to attract students who preferred public service or law studies. As the school's finances worsened, it accepted high‑school graduates, uncertified examiners, and freelance auditors who took non‑certificated courses.