The Folger Shakespeare Library is an independent research library on Capitol Hill in Washington, D.C., United States. It has the world's largest collection of the printed works of William Shakespeare, and is a primary repository for rare materials from the early modern period (1500–1750) in Britain and Europe. The library was established by Henry Clay Folger in association with his wife, Emily Jordan Folger. It opened in 1932, two years after his death.

A research library is a library that contains an in-depth collection of material on one or several subjects. A research library will generally include an in-depth selection of materials on a particular topic or set of topics and contain primary sources as well as secondary sources. Research libraries are established to meet research needs and, as such, are stocked with authentic materials with quality content. Research libraries are typically attached to academic or research institutions that specialize in that topic and serve members of that institution. Large university libraries are considered research libraries, and often contain many specialized branch research libraries. The libraries provide research materials for students and staff of these organizations to use and can also publish and carry literature produced by these institutions and make them available to others. Research libraries could also be accessible to members of the public who wish to gain in-depth knowledge on that particular topic.