diff --git a/browser/config/mozconfigs/linux32/debug b/browser/config/mozconfigs/linux32/debug
index b95976e5c2d1..232836744a6b 100644
--- a/browser/config/mozconfigs/linux32/debug
+++ b/browser/config/mozconfigs/linux32/debug
@@ -1,7 +1,6 @@
 ac_add_options --enable-debug
 ac_add_options --enable-trace-malloc
 ac_add_options --enable-signmar
-ENABLE_MARIONETTE=1
 
 . $topsrcdir/build/unix/mozconfig.linux32
 
diff --git a/browser/config/mozconfigs/linux64/debug b/browser/config/mozconfigs/linux64/debug
index 3ce1ddd55e8d..c917660e08d5 100644
--- a/browser/config/mozconfigs/linux64/debug
+++ b/browser/config/mozconfigs/linux64/debug
@@ -1,7 +1,6 @@
 ac_add_options --enable-debug
 ac_add_options --enable-trace-malloc
 ac_add_options --enable-signmar
-ENABLE_MARIONETTE=1
 
 . $topsrcdir/build/unix/mozconfig.linux
 
diff --git a/browser/config/mozconfigs/macosx64/debug b/browser/config/mozconfigs/macosx64/debug
index d57a85485b60..ebf8099456b9 100644
--- a/browser/config/mozconfigs/macosx64/debug
+++ b/browser/config/mozconfigs/macosx64/debug
@@ -4,7 +4,6 @@ ac_add_options --enable-debug
 ac_add_options --enable-trace-malloc
 ac_add_options --enable-accessibility
 ac_add_options --enable-signmar
-ENABLE_MARIONETTE=1
 
 # Needed to enable breakpad in application.ini
 export MOZILLA_OFFICIAL=1
diff --git a/browser/config/mozconfigs/win32/debug b/browser/config/mozconfigs/win32/debug
index 3d2d22b9e38b..ad878ede5d2b 100644
--- a/browser/config/mozconfigs/win32/debug
+++ b/browser/config/mozconfigs/win32/debug
@@ -5,8 +5,6 @@ ac_add_options --enable-trace-malloc
 ac_add_options --enable-signmar
 ac_add_options --enable-metro
 
-ENABLE_MARIONETTE=1
-
 # Needed to enable breakpad in application.ini
 export MOZILLA_OFFICIAL=1
 
diff --git a/browser/config/mozconfigs/win64/debug b/browser/config/mozconfigs/win64/debug
index 0d7d4443f386..a907b9e9037a 100644
--- a/browser/config/mozconfigs/win64/debug
+++ b/browser/config/mozconfigs/win64/debug
@@ -7,7 +7,6 @@ ac_add_options --enable-debug
 ac_add_options --enable-trace-malloc
 ac_add_options --enable-signmar
 ac_add_options --enable-metro
-ENABLE_MARIONETTE=1
 
 # Needed to enable breakpad in application.ini
 export MOZILLA_OFFICIAL=1