The Library began its life in 1947 with the establishment of the Economic Commission for Asia and the Far East (ECAFE), which was originally based in Shanghai, China. ECAFE had the aim of assisting with the rehabilitation of war-damaged countries in the region. Initially, each individual division of the ECAFE secretariat collected their own resources, books and publications, but as these collections grew larger and more difficult to manage, it became increasingly obvious that these collections needed to be merged and centralized. A professional Librarian was recruited in 1950 to organize and develop a functional library service, and was provided with a budget of $4000, and a staff consisting of themselves, an assistant, and a clerk.

In 1953 ECAFE moved from Shanghai to Bangkok, and as the size, scope and geographical reach of ECAFE activities continued to expand, so did the need for quality library services. The Library was becoming increasingly popular with ECAFE staff, as well as with external users who could not easily obtain material elsewhere in the region. To adjust to this growing demand, the Library sought further funding, resulting in the provision of a $25,000 grant from the Ford Foundation in 1954. This funding allowed the Library to purchase new publications and equipment, and to enhance the collection in subject areas specifically related to the work of ECAFE, such as economic development and planning, trade and finance, agriculture, resources and statistics.

In 1974 the Commission changed its name from ECAFE to ESCAP (Economic and Social Commission of Asia and the Pacific) to reflect both the social and economic aspects of development in the region, and the geographical location of its member countries. Accordingly, the ECAFE Library became the ESCAP Library, and upon completion of the new UN complex in 1975, the ESCAP Library moved to its current location on the first floor of the Service Building.

The Library acquired its first two computers in 1981. This signaled the beginning of the move to computer-based library systems, and on the 20th of July the Library introduced the ESCAP Bibliographic Information System (EBIS), which provided bibliographic descriptions of items, such as monographs and serials, and enabled users to locate these items in the Library. In 1996 the Library went online, and in 1999 the Library’s UN Documents Unit acquired the Optical Disk System (now known as ODS - Official Documents System), which provided online access to the full text of United Nations documentation.

The Library launched its own web page in 2000, and also became a member of the United Nations System Electronic Information Acquisition Consortium (UNSEIAC), a group of UN family libraries and information centre’s which facilitates access to online electronic resources. In 2004 a comprehensive physical renovation took place to modernize the library premises, and in 2006, the Library undertook the project of digitizing ESCAP official documents. Almost all of the retrospective ECAFE/ESCAP documents were scanned and the Library is continuing the time consuming work of indexing these documents and making them available online.

In the spirit of UN reform and a focus on pooling of common services, the concept of a 'One UN' Library at Bangkok was discussed among the Organization Management Team of various UN agencies based in Bangkok. Starting September of 2007, a number of regional UN agencies (included UNICEF and UNESCO) weeded out their library collections and forwarded remaining books for integration into the United Nations ESCAP Library collection.