 K&K Ulf Krüger oHG Germany | 1 | 2000 |
| K&N Germany | 1 | 1990 |
 K. A. Hagström Sweden | 4 | 1897 - 1901 |
 K. Guvussis Greece | 2 | |
| K. Thienemanns Verlag, Stuttgart Germany | 6 | 1939 - 1968 |
 K.B.S. Erica Netherlands | 1 | 2003 |
 K.E. Media Denmark | 1 | 2004 |
 K.G. Murray Publishing Co. Pty. Ltd. Australia | 1 | 1970 |
| Kabel Verlag, München Germany | 1 | 2001 |
 KaBoom! USA | 2 | 2013 - 2016 |
| Kabusa Böcker Sweden | 5 | 2012 - 2017 |
 Kadokawa Shoten Japan | 1 | 1982 |
 Kagra Poland | 1 | 2004 |
| Kahley House Publishing USA | 1 | 2008 |
 Kahn & Averill UK | 1 | 1997 |
 Kailash Czech Republic | 1 | 2015 |
| Kaiser Germany | 3 | 2005 |
 Kaiser Austria | 1 | 1982 |
| Kaleidoscope Publishing UK | 2 | 2021 |
| Kaleidoskop Germany | 1 | 2006 |
| Kalla Kårar Sweden | 5 | 1975 - 1977 |
| Kalla Kulor Förlag Sweden | 4 | 2012 - 2014 |
| Kalmar Stifts Herdaminneskommitté Sweden | 1 | 1948 |
| Kalmbach Books USA | 148 | 1943 - 2024 |
| Kalmbach Publishing USA | 1 | 1968 |
| Kalmus USA | 2 | 1985 |
| Kamera UK | 1 | 2003 |
| Kamp Germany | 1 | 1991 |
 Kampa Switzerland | 1 | 2019 |
| Kandour Ltd. UK | 1 | 2005 |
 Kangaroo Books Canada | 3 | 1978 - 1979 |
| Karakter Uitgevers Netherlands | 1 | 2002 |
 Karisto Finland | 3 | 2007 - 2014 |
| Karl Blessing Verlag Germany | 8 | 1997 - 2012 |
| Karl Dietz Verlag Germany | 1 | 2004 |
| Karl Emil Knudsen Denmark | 10 | 1966 - 1970 |
| Karl Hart KG Germany | 1 | 1972 |
| Karl Heyde Verlag, Stuttgart Germany | 3 | |
| Karl May - Bücherei Bamberg Germany | 2 | 1950 - 1962 |
| Karl May - Verlag Bamberg Germany | 3 | |
| Karl Müller Verlag Germany | 8 | 2009 |
| Karl Rauch Verlag Germany | 2 | 1952 - 1962 |
| Karl-Erik Gavelin Sweden | 2 | 1994 |
| Karl-May-Verlag Germany | 24 | 1929 - 2020 |
 Karmat Press Romania | 1 | 1993 |
| Kärnan Sweden | 1 | |
| Karstu-Karkali Seura Finland | 1 | 2007 |
| Kartographischer Verlag Busche GmbH Germany | 1 | 1974 |
| Katbard Publishing USA | 1 | 2015 |
| Kaufhof AG Germany | 1 | 1977 |
| KAW Poland | 1 | 1985 |
| Kawabata Press UK | 1 | 1989 |
| Kawade Shobo Shinsha Publishers Japan | 1 | 2008 |
| Kawasaki International | 1 | 2016 |
| Kaye & Ward UK | 15 | 1945 - 1985 |
| Kaye Publications UK | 7 | 1950 - 1954 |
| Kaye-Wood Publications UK | 1 | 1945 |
| Kaytis Publications USA | 1 | 1991 |
| Kaywin Publishers USA | 7 | 1951 - 1952 |
 Kazanlashka Dolina Bulgaria | 1 | 1937 |
| KBV Germany | 7 | 1995 - 2016 |
| KC Publications Inc. USA | 4 | 1989 |
| Keats Publishing, Inc. USA | 1 | 1973 |
| Keen Press USA | 1 | 2019 |
| Kegan Paul, Trench, Trübner & Co. UK | 1 | 1907 |
| Kegan Paul,Trench & Co. UK | 1 | 1883 |
| Kehrer Verlag KG, Freiburg Im Breisgau Germany | 1 | 1988 |
| Kein & Aber Switzerland | 2 | 2007 |
| Keith Wease USA | 1 | 2013 |
| Kellner Germany | 1 | 1991 |
| Kelsey UK | 1 | 2005 |
| Kelsey Publishing UK | 2 | 2023 - 2024 |
| Kelter Pockets Germany | 1 | |
| Kelter Taschenbuch Germany | 4 | 1970 - 1980 |
| Kempen Pers, Hapert Netherlands | 1 | 1992 |
| Ken Borden Ltd. Canada | 1 | 1967 |
 Kendalc'h France | 1 | 1971 |
| Kendall Hunt USA | 1 | 2000 |
| Kenneth Mason UK | 2 | 1965 - 1973 |
| Kennikat Press USA | 1 | 1964 |
 Kennys Bookshop And Art Galleries Limited Ireland | 1 | 1982 |
| Kensington Books USA | 1 | 2018 |
| Kentaur Yugoslavia | 1 | 1977 |
| Kerber Germany | 1 | 2009 |
| Kern County Museum USA | 1 | 2009 |
| Kerosina Books UK | 3 | 1986 - 1988 |
| Key Book UK | 1 | 1960 |
| Key Porter Books Canada | 2 | 1982 - 2008 |
| Key Publishing UK | 10 | 2012 - 2020 |
| Keyprints Press UK | 3 | 2008 |
| Keys USA | 1 | 1964 |
| Keywords Press USA | 3 | 2015 - 2016 |
| Kibu-Verlag Germany | 2 | 1979 - 1981 |
| Kickerz Sweden | 1 | 2013 |
| Kicks Books USA | 2 | 2012 - 2020 |
| Kiddicraft UK | 1 | 1977 |
| Kids Can Press USA | 1 | 2019 |
| Kiepenheuer Germany | 1 | 2008 |
| Kiepenheuer & Witsch Germany | 85 | 1958 - 2024 |
| Kimberley's UK | 3 | 1982 - 1984 |
| Kinderbuch Verlag, Berlin East Germany | 14 | 1966 - 1989 |
| Kindler Verlag, München Germany | 9 | 1956 - 2022 |
 King Fahd Complex Saudi Arabia | 1 | 1998 |
| King Kong Australia | 1 | 2019 |
| King Penguin USA | 1 | 1990 |
| Kingfisher UK | 7 | 1989 - 2004 |
| Kingfisher USA | 2 | 2002 - 2003 |
| Kingfisher Reach Communications Ltd. UK | 1 | 2013 |
| Kingly-Reprieve UK | 1 | 2006 |
| Kingsley Publishing Canada | 2 | 2009 - 2012 |
| Kingston Korner USA | 1 | 1986 |
| Kingston Library UK | 1 | 1954 |
| Kingston Upon Hull City Council UK | 1 | 1996 |
| Kira Förlag Sweden | 1 | 2021 |
| Kirjakauppaliitto Finland | 2 | 2013 - 2015 |
| Kirjapaja Finland | 1 | 1978 |
| Kirjayhtymä Finland | 4 | 1973 - 1986 |
| Kishorn Publications Canada | 2 | 1987 - 1994 |
| Kisstory II Ltd. USA | 1 | 1999 |
| Kitchen Sink Press USA | 9 | 1989 - 1998 |
| Kiwi France | 1 | 2018 |
| Kiwi Publishing USA | 1 | 2023 |
| Klartext Germany | 2 | 2021 - 2022 |
| Klassikerförlaget Sweden | 1 | 1998 |
| Klaus Reprint Co. USA | 1 | 1973 |
| Kleins Druck- Und Verlagsanstalt Lengerich Germany | 4 | 1949 - 1951 |
| Klematis Denmark | 1 | 2003 |
| Klett Germany | 12 | 1973 - 2016 |
| Klett / Tropen Germany | 2 | 2014 - 2015 |
| Klett-Cotta Germany | 3 | 1998 - 2014 |
| KLG Press UK | 1 | 2010 |
| Klinkhardt & Biermann, Braunschweig Germany | 2 | 1955 - 1981 |
| KLMN Bulgaria | 1 | 2009 |
| Klubb Super 8 Sweden | 1 | 2021 |
| Kluitman Netherlands | 18 | 1907 - 2000 |
| Klüsener Germany | 1 | 1988 |
| Klutz USA | 12 | 1994 - 2018 |
| Kňap Jaroslav - Karpana Czech Republic | 1 | 2014 |
| KNAUF Germany | 1 | |
| Knaur Germany | 102 | 1956 - 2021 |
| Knickerbocker USA | 1 | |
| Knickerbocker Press USA | 1 | 1895 |
| Knight UK | 17 | 1968 - 1987 |
| Knight Books Canada | 2 | 1978 |
| Knightsbridge Publications UK | 1 | 1969 |
| Knightsbridge Publishing USA | 1 | 1991 |
| Knigomania Bulgaria | 2 | 2008 - 2017 |
| Knockabout UK | 16 | 1983 - 2014 |
| Knockabout Publications UK | 1 | 1987 |
| Knopf Australia | 4 | 2008 - 2012 |
| Know The Score Books UK | 1 | 2008 |
| Kodansha Japan | 1 | 1998 |
| Kodansha International USA | 1 | 1997 |
| Kodansha International International | 2 | 1981 - 2010 |
| Kodansha International Ltd. Japan | 1 | 1966 |
| Koehler & Amelang, Leipzig Germany | 2 | 1933 - 1934 |
| Koehlers Verlagsgesellschaft, Biberach / Riss Germany | 1 | 1958 |
| Koehlers Verlagsgesellschaft, Hamburg Germany | 1 | 1995 |
| Koehlers Verlagsgesellschaft, Herford Germany | 4 | 1971 - 1985 |
| Kogan Page UK | 7 | 1988 - 2008 |
| KOHA-Verlag GmbH, Burgrain Germany | 1 | 2007 |
| Kohner, Madison & Danforth USA | 3 | 2015 - 2017 |
| Kok Kampen Netherlands | 3 | 1979 - 1990 |
| Kolibri-Verlag, Wuppertal Germany | 6 | 1976 |
| Koman Germany | 1 | 1998 |
| Komedia Entertainment UK | 1 | 2019 |
| Komet Germany | 5 | 2004 - 2005 |
| Komma & Clausen Denmark | 1 | 1992 |
| Kommanditbolaget Chelius & Co Sweden | 1 | 1913 |
| Kompas Bulgaria | 1 | 1992 |
| Kompass-Karten Germany | 1 | 2015 |
| Konecky & Konecky USA | 4 | 1960 - 2006 |
| Koneman & Aperture Foundation USA | 1 | 1997 |
| Könemann International | 4 | 1996 |
 Könemann Europe | 3 | 2001 - 2013 |
| Könemann Germany | 6 | 1996 - 1999 |
| Könemann Sweden | 1 | 1999 |
 Könemann Music Budapest Hungary | 1 | 1999 |
| Kongl. Maj:ts Vetenskaps Akademi Sweden | 32 | 1875 - 1945 |
| Konkret Literatur Verlag Germany | 1 | 1994 |
| Konrad Theiss Verlag Germany | 2 | 2008 - 2017 |
| Könyvmolyképz? Kiadó Hungary | 1 | 2008 |
| Kooperativa Förbundets Bokförlag Sweden | 2 | 1949 |
| Kopp Verlag Germany | 2 | 2007 - 2017 |
| Kösel Germany | 2 | 1961 - 2003 |
| Kösel Verlag - München Germany | 3 | 1930 - 1963 |
| Kosmos Yugoslavia | 1 | 1960 |
| Kosmos Germany | 15 | 1928 - 2022 |
| Kosmos Netherlands | 4 | 1998 - 2005 |
| Kossuth Kiadó Hungary | 1 | 1966 |
| Koudansha (講談社) Japan | 1 | 1979 |
 Kowalski Italy | 1 | 2004 |
| Kozmik Press USA | 2 | 1982 |
| Kozy Books USA | 7 | 1960 - 1962 |
| KP USA | 3 | 2000 - 2005 |
| Kramer'sche Sortiments-Buchhandlung Germany | 1 | |
| Kramers Netherlands | 1 | |
| Kratville Publisher USA | 1 | 1976 |
| Krause Publications USA | 54 | 1989 - 2020 |
| Kremayr & Scheriau Germany | 1 | 2001 |