diff --git a/backend/src/langs.ts b/backend/src/langs.ts
index bb68fc9..181e021 100644
--- a/backend/src/langs.ts
+++ b/backend/src/langs.ts
@@ -1256,6 +1256,19 @@ int main() {
       code: `x = 123 * 234`,
     },
     template: `print("Hello, world!")
+`,
+  },
+  gnuplot: {
+    name: "Gnuplot",
+    repl: "gnuplot",
+    input: `print 123 * 234`,
+    main: "main.gnuplot",
+    run: "gnuplot main.gnuplot -",
+    scope: {
+      code: `x = 123 * 234`,
+      input: `print x`,
+    },
+    template: `print "Hello, world!"
 `,
   },
   go: {
diff --git a/scripts/docker-install-phase3b.bash b/scripts/docker-install-phase3b.bash
index 319b897..a27cac8 100755
--- a/scripts/docker-install-phase3b.bash
+++ b/scripts/docker-install-phase3b.bash
@@ -63,6 +63,9 @@ golang
 # Groovy
 groovy
 
+# Gnuplot
+gnuplot
+
 # Hack
 hhvm