| 501 |
Japan Advanced Institute of Science and Technology | Japan | academic | | | |
| 502 |
Japan International Cooperation Agency | Japan | other | | | |
| 503 |
Jet Propulsion Laboratory, California Institute of Technology/NASA | United States | government | | | |
| 504 |
Jikei University | Japan | academic | | | |
| 505 |
Jimma University Library System | Ethiopia | academic | 1.6.x JSP | | |
| 506 |
Joetsu University of Education | Japan | academic | | | |
| 507 |
Johns Hopkins University | United States | academic | | | |
| 508 |
Joint Research Centre | Italy | research center | 1.5.x JSP | | |
| 509 |
Jozef Pilsudski Institute of America | United States | nonprofit | 1.7.x XML Manakin | | |
| 510 |
Junta Central Electoral | Dominica | government | | | |
| 511 |
Kagoshima University | Japan | academic | | | |
| 512 |
Kaiser Permanente | United States | nonprofit | 1.7.x XML Manakin | | |
| 513 |
Kalamazoo College | United States | academic | | | |
| 514 |
Kanagawa Institute of Technology | Japan | academic | | | |
| 515 |
Kanagawa University | Japan | academic | | | |
| 516 |
Kanazawa University | Japan | academic | 1.6.x JSP | | |
| 517 |
Kansai University | Japan | academic | | | |
| 518 |
Kansas State Publications Archival Collection, KSPACe | United States | government | | | |
| 519 |
Kansas State University, K-REx | United States | academic | 1.4.x | | |
| 520 |
Kapila Khandvala College of Education | India | academic | 1.3.x and earlier | | |
| 521 |
Karolinska Institutet | Sweden | academic | | | |
| 522 |
Kasetsart University, Computer Engineering | Thailand | academic | 1.4.x | | |
| 523 |
Katholieke Universiteit (K.U.Leuven), LIRIAS | Belgium | academic | | | |
| 524 |
Kauno kolegija/Kaunas University of Applied Science | Lithuania | academic | 1.7.x JSP | | |
| 525 |
Kazakh National University | Kazakhstan | academic | 1.3.x and earlier | | |
| 526 |
KCA University | Kenya | academic | 1.8.x JSP | | |
| 527 |
Keio University | Japan | academic | | | |
| 528 |
Kentucky Department for Libraries and Archives | United States | government | 1.7.x JSP | | |
| 529 |
Kenya Power, Stima Plaza | Kenya | other | 1.7.x JSP | | |
| 530 |
Kenyatta University | Kenya | academic | 1.7.x XML Manakin | | |
| 531 |
Kerch State Maritime Technological University | Ukraine | academic | 1.7.x JSP | | |
| 532 |
Kharkiv National University of Radioelectronics | Ukraine | academic | | | |
| 533 |
Kharkov National Automobile and Highway University | Ukraine | academic | | | |
| 534 |
Khazar University | Azerbaijan | academic | | | |
| 535 |
Khmelnitskiy National University | Ukraine | academic | | | |
| 536 |
Khon Kaen University | Thailand | academic | | | |
| 537 |
Khulna University of Engineering & Technology | Bangladesh | academic | 1.8.x JSP | | |
| 538 |
King Saud Unuversity | Saudi Arabia | academic | 1.5.x JSP | | |
| 539 |
Kitami Institute of Technology | Japan | academic | | | |
| 540 |
Kochi University | Japan | academic | | | |
| 541 |
Kochi University of Technology | Japan | academic | | | |
| 542 |
Korea Advanced Institute of Science and Technology (KAIST) | South Korea | academic | | | |
| 543 |
Korea Consumer Agency | Korea Dem. People's Rep. | other | | | |
| 544 |
Korea Institute for Health and Social Affairs | South Korea | research center | | | |
| 545 |
Korea Institute for Internatioal Economic Policy | South Korea | government | | | |
| 546 |
Korea Institute of Geoscience and Mineral Resource | South Korea | research center | 1.4.x | | |
| 547 |
Ksi??nica Stargardzka | Poland | national library | 1.7.x XML Manakin | | |
| 548 |
ktree | India | commercial | 1.5.x JSP | | |
| 549 |
Kumamoto University | Japan | academic | | | |
| 550 |
Kun Shan University | Taiwan | academic | 1.4.x | | |
