LII began in the early 1990s as a Gopher bookmark file maintained by reference librarian Carole Leita. In October 1994, LII migrated to a website and was renamed Berkeley Public Library Index to the Internet.

In late 1996, Carole began working with Roy Tennant at UC Berkeley’s Digital Library SunSITE to add a search engine to LII, and develop a content management system to make it easier to add and maintain entries. LII catalogers also began adding Library of Congress Headings to LII items.

In March 1997, the Berkeley Public Library Index to the Internet moved to UC Berkeley SunSITE and was renamed the Librarians' Index to the Internet (LII). 1997 was also the first year LII received funding through the Library Services and Technology Act (LSTA), state funds from the Institute for Museum and Library Services, distributed in California by the State Librarian. Some of this funding was used to pay for additional editorial support, and some funding was used to recruit and train volunteer contributors.

In 1998, a mailing list for weekly updates was established.

In 2001, founder Carole Leita retired, and Karen G. Schneider came on board as director. At this point, LII's funding was through the Library of California.

2002 featured a number of design improvements, including addition of a spell-checker and search results sorted by relevance ranking. The primary funding source switched back to LSTA, distributed through the California State Library.

In 2003, LII began working with Washington State Library on a collaborative project, and partnered with California Digital Library on a content-creation project.

In 2004, LII began the development planning to migrate to a new database-driven website. In 2004 we also debuted our RSS subscription option, which was immediately very popular.

In late September 2005, LII moved to a new content management system with many new features inside and out. Our hosting provider and lead development company changed to Community Servers, Inc., a small company based in Glen Ellen, California. We also shortened our name to Librarians’ Internet Index, and rolled out a new design and logo.

Future plans include a new search engine.