| Labrant Dennis | 1996 | USA | 2 |
| Lakhvir Kaur Singh | 2008 - 2009 | United Kingdom | 1 |
| Lam Kor-wan | 1982 | Hong Kong | 4 |
| Lam Kwok-wai | 1992 - 1993 | Hong Kong | 3 |
| Lance Collin Shockley | 2005 | USA | 1 |
| Lao Rongzhi | 1996 - 1999 | China | 7 |
| Larissa Schuster | 2003 | USA | 1 |
| Larme Price | 2003 | USA | 4 |
| Larry Allen Hayes | 1999 | USA | 2 |
| Larry Davis | 1983 - 1986 | USA | 1 |
| Larry Dean Bright | 2003 - 2004 | USA | 8+ |
| Larry DeWayne Hall | 1993 | USA | 2 |
| Larry Donnell Andrews | 1986 | USA | 2 |
| Larry Eyler | 1982 - 1984 | USA | 21+ |
| Larry Gene Ashbrook | 1999 | USA | 7 |
| Larry Gene Bell | 1985 | USA | 2+ |
| Larry Gene Heath | 1981 | USA | 1 |
| Larry Gilbert | 1977 | USA | 1 |
| Larry Green | 1972 - 1974 | USA | 15+ |
| Larry Griffin | 1980 | USA | 1 |
| Larry Lamont White | 1983 | USA | 3 |
| Larry Lee Ranes | 1964 | USA | 2+ |
| Larry Ralston | 1975 - 1977 | USA | 5+ |
| Larry Tacklyn | 1973 | Bermuda | 2 |
| Laura Jeanne Taylor | 1992 | USA | 6 |
| Laurence Shirley | 1760 | United Kingdom | 1 |
| Laurie Dann | 1988 | USA | 1+ |
| Lavinia May Burnett | 1845 | USA | 1 |
| Lawrence Paul Mills III | 2017 | USA | 3+ |
| Lawrence Russell Brewer | 1998 | USA | 1 |
| Lawrence Sigmund Bittaker | 1979 | USA | 5+ |
| Lawrence Yunkin | 1991 | USA | 1 |
| Lawrencia Ann Bembenek | 1981 | USA | 1 |
| Lázaro Barbosa de Sousa | 2007 - 2021 | Brazil | 6 |
| Lê Thanh Vân | 1998 - 2001 | Vietnam | 13+ |
| Léa Papin | 1933 | France | 2 |
| Lee Boyd Malvo | 2002 | USA | 10+ |
| Lee Chi-hang | 1982 | Hong Kong | 6 |
| Lee Chun-jae | 1986 - 1994 | South Korea | 15 |
| Lee Ford | 2000 | United Kingdom | 5 |
| Lee Ho-seong | 2008 | South Korea | 4 |
| Lee Monroe Betterton | 1904 - 1919 | USA | 3 |
| Lee Roy Martin | 1967 - 1968 | USA | 4 |
| Lemaricus Devall Davidson | 2007 | USA | 2 |
| Lemuel Warren Smith | 1958 - 1981 | USA | 6 |
| Lena Baker | 1944 | USA | 1 |
| Leo Held | 1967 | USA | 6 |
| Leon David Dorsey IV | 1994 | USA | 3 |
| Leon Davis Jr. | 2007 | USA | 5 |
| Leon Frank Czolgosz | 1901 | USA | 1 |
| Leonard John Fraser | 1998 - 1999 | Australia | 4+ |
| Leonard Keith Lawson | 1962 | Australia | 2 |
| Leonard Lake | 1983 - 1985 | USA | 11+ |
| Leonard Patrick Gonzalez Jr. | 2009 | USA | 2 |
| Leonard Patrick Gonzalez Sr. | 2009 | USA | 2 |
| Leonard Peltier | 1975 | USA | 2 |
| Leonarda Cianciulli | 1939 | Italy | 3 |
| Leonardas Zavistonovičius | 1998 | Lithuania | 9 |
| Leonel Torres Herrera | 1981 | USA | 1 |
| Léopold Dion | 1963 | Canada | 4 |
| Leroy Hall Jr. | 1991 | USA | 1 |
| Leroy Snyder | 1969 | USA | 7 |
| Lesley Eugene Warren | 1987 - 1990 | USA | 4 |
| Leslie Alfred Camilleri | 1997 | Australia | 2 |
| Leslie Allen Williams | 1991 - 1992 | USA | 4 |
| Leslie Dale Martin | 1991 | USA | 1 |
| Leslie Irvin | 1954 - 1955 | USA | 6+ |
| Leslie Leon Burchart | 1994 - 1996 | USA | 3+ |
| Leslie Louise Van Houten | 1969 | USA | 1 |
| Lester Ford | 1991 | USA | 3 |
| Lester Harrison | 1951 - 1973 | USA | 5-7 |
| Lester Leroy Bower Jr. | 1983 | USA | 4 |
| Lester Warfel Brockelhurst Jr. | 1937 | USA | 3+ |
| Leszek Jacek Pękalski | 1984 - 1992 | Poland | 1 |
| Letalvis Darnell Cobbins | 2007 | USA | 2 |
| Levi Aron | 2011 | USA | 1 |
| Levi Bellfield | 2002 - 2004 | United Kingdom | 3+ |
| Levi Boone Helm | 1850 - 1864 | USA | 11+ |
| Lewis Eugene Gilbert II | 1994 | USA | 4 |
| Lewis Hutchinson | 1760 - 1773 | Jamaica | 40+ |
| Li Hao | 2009 - 2011 | China | 2 |
| Li Hsing-ju | 1959 | China | 10 |
| Li Wenxiang | 1991 - 1996 | China | 13 |
| Licho Escamilla | 2001 | USA | 1 |
| Lin Yu-ju | 2008 - 2009 | Taiwan | 3 |
| Linda Anita Carty | 2001 | USA | 1 |
| Linda Calvey | 1986 - 1991 | United Kingdom | 1 |
| Linda Darlene Kasabian | 1969 | USA | 7 |
| Linda Henning | 1999 | USA | 1 |
| Linda Laura Hazzard | 1908 - 1912 | USA | 15 |
| Linda Mulhall | 2005 | Ireland | 1 |
| Lindsay Hoani Beckett | 1997 | Australia | 2 |
| Lindsey Robert Rose | 1984 - 1994 | Australia | 5 |
| Linwood Earl Briley | 1979 | USA | 12+ |
| Linwood Earl Forte | 1990 | USA | 3 |
| Lisa Ann Coleman | 2004 | USA | 1 |
| Lisa Jo Chamberlin | 2004 | USA | 2 |
| Lisa Marie Montgomery | 2004 | USA | 1 |
| Lisa Michelle Lambert | 1991 | USA | 1 |
| Lisl Auman | 1997 | USA | 1 |
| Liu Zhanjin | 2000 | China | 39 |
| Liz Carroll | 2006 | USA | 1 |
| Ljubiša Bogdanović | 2013 | Serbia | 13 |
| Lloyd Gomez | 1950 - 1951 | USA | 9 |
| Lloyd Maurice Crosbie | 2001 | Australia | 2 |
| Lois Germaine Josephine Zerwas Jurgens | 1965 | USA | 1 |
| Long Zhimin | 1983 - 1985 | China | 48 |
| Lonnie David Franklin Jr. | 1984 - 2007 | USA | 10+ |
| Loran Kenstley Cole | 1994 | USA | 2 |
| Loren Herzog | 1984 - 1998 | USA | 4+ |
| Lorenzo Fayne | 1989 - 1993 | USA | 6 |
| Lorenzo Jerome Gilyard Jr. | 1977 - 1993 | USA | 6+ |
| Lori Ryan Daybell | 2019 - 2020 | USA | 5 |
| Lorne Joe Acquin | 1977 | Canada | 9 |
| Lorraine Thorpe | 2009 | United Kingdom | 2 |
| Louay Omar Mohammed al-Taei | 2005 - 2006 | Iraq | 43 |
| Louis Bernard Gaskin | 1986 - 1989 | USA | 2 |
| Louis Buchalter | 1935 - 1936 | USA | 1+ |
| Louis Craine | 1984 - 1987 | USA | 4+ |
| Louis D. Hastings | 1983 | USA | 6 |
| Louis Jones Jr. | 1995 | USA | 1 |
| Louis-Amadeo Brihier Lacroix | 1882 - 1906 | France | 6 |
| Louisa May Merrifield | 1953 | United Kingdom | 1 |
| Louise Peete | 1912 - 1944 | USA | 3+ |
| Louise Vermilya | 1893 - 1911 | USA | 9 |
| Lowell Edwin Amos | 1979 - 1994 | USA | 4 |
| Lowell Lee Andrews | 1958 | USA | 3 |
| Ľubomír Harman | 2010 | Slovakia | 7 |
| Lucien Carr | 1944 | USA | 1 |
| Lucien Léger | 1964 | France | 1 |
| Lucious Boyd | 1993 - 1999 | USA | 1+ |
| Lucky Ward | 2010 | USA | 2 |
| Lucy Letby | 2015 - 2016 | United Kingdom | 7+ |
| Ludwig Tessnow | 1898 - 1901 | Germany | 4 |
| Luigi Chiatti | 1992 - 1993 | Italy | 2 |
| Luis Alfredo Garavito Cubillos | 1992 - 1999 | Colombia | 193+ |
| Luis Bracamontes | 2014 | Mexico | 2+ |
| Luis Gregorio Ramírez Maestre | 2010 - 2012 | Colombia | 30 |
| Luis Ignacio Vásquez Villenas | 2022 - 2023 | Chile | 4 |
| Luis José Monge | 1963 | USA | 4 |
| Luís Miguel Militão Guerreiro | 2001 | Portugal | 6 |
| Luísa de Jesus | 1760 - 1772 | Portugal | 33+ |
| Luiz Henrique de Lima | 2023 | Brazil | 4 |
| Luka Rocco Magnotta | 2012 | Canada | 1 |
| Luo Shubiao | 1977 - 1994 | China | 19 |
| Lyda Southard | 1915 - 1920 | USA | 1+ |
| Lydia Echevarría | 1983 | Puerto Rico | 1 |
| Lydia Sherman | 1863 - 1877 | USA | 11 |
| Lyle Richard Brummett | 1975 - 1976 | USA | 3 |
| Lynda Cheryle Lyon Block | 1993 | USA | 1 |
| Lynwood Crumpler Drake III | 1992 | USA | 6 |
