- Ada
- C (Tcl of course!)
- C++
- D
- Dylan
- Erlang
- FORTH
- FORTRAN
- Frontier-Tk
- Go (gothic)
- Guile
- Haskell
- J++ binding to Tcl (no info on whether Tk was actually a part of that project)
- Java (via TclBlend or Jacl/Swank)
- Ksh (aka Tksh/dtksh)
- Common Lisp
- Limbo in Inferno [1]
- Lua
- Mercury
- Mozart
- OCaml
- Perl
- Phantom/Modula-3
- Prolog
- Pure [2]
- Python
- R
- Rexx
- Ruby
- Scheme
- SNOBOL (CSnobol4)
- Yorick
- ... probably many others ...