| Jai | procedural programming | — | — |
| Jakarta Expression Language | — | — | Eclipse Foundation |
| Jakt | — | 2022 | Andreas Kling |
| JAL | procedural programming | 2003 | — |
| JaM | — | 1978 | Martin Newell, John Warnock |
| Janet | — | — | — |
| Janus | imperative programming, reversible computing, procedural programming | 1982 | — |
| Janus | concurrent constraint logic programming | 1990 | — |
| JANUS (AI control threshold) | — | — | CAI Technology |
| Jasmin | object-oriented programming | — | — |
| JASS | — | 2001 | Blizzard Entertainment |
| Java | object-oriented programming, generic programming, component-based software engineering, concurrent object-oriented programming, class-based programming, imperative programming, structured programming, functional programming, reflective programming | 1995 | Sun Microsystems, Oracle Corporation, James Gosling |
| Java 21 | — | — | — |
| Java Agent Development Framework | — | — | — |
| JavaFX Script | scripting language, declarative programming | 2008 | Sun Microsystems |
| JavaScript | generic programming, aspect-oriented programming, imperative programming, functional programming, prototype-based programming, event-driven programming | 1995 | — |
| JavaScript for Automation | — | — | Apple Inc. |
| Jeem | — | — | — |
| Jess | logic programming, declarative programming | 1995 | Sandia National Laboratories |
| Jim Tcl | — | — | — |
| Jmax | — | — | — |
| JModelica.org | declarative programming | — | — |
| JoCaml | — | — | Institut National de Recherche en Informatique et en Automatique |
| Joe-E | Object-capability model | 2004 | — |
| Join Java | reflective programming, concurrent computing, procedural programming | 2000 | Stewart Von Itzstein |
| Join-pattern | concurrent computing | — | — |
| Jolie | — | — | Fabrizio Montesi |
| JOSS | — | 1963 | Cliff Shaw |
| Joule | object-oriented programming, imperative programming, dataflow programming | 1996 | — |
| JOVIAL | imperative programming, structured programming, procedural programming | 1960 | — |
| Joy | purely functional programming, concatenative programming, stack-oriented programming | 2001 | — |
| Joyce | concurrent computing, procedural programming | — | Per Brinch Hansen |
| Jq | tacit programming, functional programming | 2012 | Stephen Dolan |
| JS++ | generic programming, functional programming, structured programming, imperative programming, object-oriented programming | 2011 | — |
| JScript | prototype-based programming, object-oriented programming | 1996 | Microsoft |
| JScript .NET | — | — | Microsoft |
| JSFuck | — | — | — |
| Jsish | multi-paradigm programming | — | Peter MacDonald |
| JSONiq | declarative programming | — | — |
| JSX | — | 2012 | DeNA |
| Judoscript | object-oriented programming | 2001 | — |
| Julia | multi-paradigm programming, imperative programming, parallel computing, functional programming, multiple dispatch, procedural programming, object-oriented programming, array programming, metaprogramming | 2009 | Viral B. Shah, Stefan Karpinski, Alan Edelman, Jeff Bezanson |
| Julia | — | — | — |
| Just BASIC | — | — | — |
| K | — | — | — |
| K | array programming, functional programming | 1993 | — |
| Kaitai Struct | — | — | — |
| Kalaam | — | — | — |