diff --git a/README.md b/README.md
index d3032da0..d14224d4 100644
--- a/README.md
+++ b/README.md
@@ -38,6 +38,7 @@ Currently supported grammars are:
 | [Erlang]                            |            | Yes             | [language-erlang]             | `erl`                     | Limited selection based runs only (see [#70]).                                                                                                                                                                                                                  |
 | [F*]                                | Yes        |                 | [atom-fstar]                  | `fstar`                   |                                                                                                                                                                                                                                                                 |
 | [F#]                                | Yes        |                 | [language-fsharp]             | `fsharpi`/`fsi.exe`       |                                                                                                                                                                                                                                                                 |
+| [Factor]                            | Yes        |                 | [language-factor]             | `factor`                    |                                                                                                                                                                                                                                                                 |
 | [Fish]                              | Yes        | Yes             | [language-fish-shell]         | `fish`                    |                                                                                                                                                                                                                                                                 |
 | [Forth]                             | Yes        |                 | [language-forth]              | `gforth`                  |                                                                                                                                                                                                                                                                 |
 | [Fortran]                           | Yes        |                 | [language-fortran]            | [`gfortran`]              |                                                                                                                                                                                                                                                                 |
@@ -156,6 +157,7 @@ Currently supported grammars are:
 [es6]: https://babeljs.io/learn-es2015
 [f*]: https://fstar-lang.org
 [f#]: http://fsharp.org
+[factor]: https://factorcode.org/
 [file]: https://atom.io/packages/language-batchfile
 [fish]: https://fishshell.com
 [forth]: https://gnu.org/software/gforth
@@ -189,6 +191,7 @@ Currently supported grammars are:
 [language-dot]: https://atom.io/packages/language-dot
 [language-elixir]: https://atom.io/packages/language-elixir
 [language-erlang]: https://atom.io/packages/language-erlang
+[language-factor]: https://atom.io/packages/language-factor
 [language-fish-shell]: https://atom.io/packages/language-fish-shell
 [language-forth]: https://atom.io/packages/language-forth
 [language-fortran]: https://atom.io/packages/language-fortran
diff --git a/lib/grammars.js b/lib/grammars.js
index 3ded67de..17e08d2d 100644
--- a/lib/grammars.js
+++ b/lib/grammars.js
@@ -7,6 +7,7 @@ import c from "./grammars/c"
 import coffeescript from "./grammars/coffeescript"
 import database from "./grammars/database"
 import doc from "./grammars/doc"
+import factor from "./grammars/factor"
 import fortran from "./grammars/fortran"
 import haskell from "./grammars/haskell"
 import * as java from "./grammars/java"
@@ -29,6 +30,7 @@ const Grammars = {
   ...coffeescript,
   ...database,
   ...doc,
+  ...factor,
   ...fortran,
   ...haskell,
   ...java,
diff --git a/lib/grammars/factor.js b/lib/grammars/factor.js
new file mode 100644
index 00000000..8ee2e060
--- /dev/null
+++ b/lib/grammars/factor.js
@@ -0,0 +1,19 @@
+"use babel"
+
+const Factor = {
+  "Selection Based": {
+    command: "factor",
+    args({ selection }) {
+      return ["-e=<< USE: parser auto-use >> " + selection.getText()]
+    },
+  },
+
+  "File Based": {
+    command: "factor",
+    args({ filepath }) {
+      return [filepath]
+    },
+  },
+}
+
+export default { Factor }