diff --git a/gerrit-gwtui/src/main/java/net/codemirror/mode/ModeInfo.java b/gerrit-gwtui/src/main/java/net/codemirror/mode/ModeInfo.java
index 85b350dc9d..debf4b7050 100644
--- a/gerrit-gwtui/src/main/java/net/codemirror/mode/ModeInfo.java
+++ b/gerrit-gwtui/src/main/java/net/codemirror/mode/ModeInfo.java
@@ -73,6 +73,7 @@ public class ModeInfo extends JavaScriptObject {
       Modes.I.soy(),
       Modes.I.sql(),
       Modes.I.stex(),
+      Modes.I.tcl(),
       Modes.I.velocity(),
       Modes.I.verilog(),
       Modes.I.vhdl(),
diff --git a/gerrit-server/src/main/resources/com/google/gerrit/server/mime/mime-types.properties b/gerrit-server/src/main/resources/com/google/gerrit/server/mime/mime-types.properties
index d93aa347e5..ea99846403 100644
--- a/gerrit-server/src/main/resources/com/google/gerrit/server/mime/mime-types.properties
+++ b/gerrit-server/src/main/resources/com/google/gerrit/server/mime/mime-types.properties
@@ -45,6 +45,7 @@ scala = text/x-scala
 soy = text/x-soy
 st = text/x-stsrc
 stex = text/x-stex
+tcl = text/x-tcl
 v = text/x-verilog
 vert = x-shader/x-vertex
 vh = text/x-verilog