diff --git a/cms/envs/common.py b/cms/envs/common.py
index 10aaa3d09689..cb5e32491f7c 100644
--- a/cms/envs/common.py
+++ b/cms/envs/common.py
@@ -1243,6 +1243,8 @@
 ##### custom vendor plugin variables #####
 # JavaScript code can access this data using `process.env.JS_ENV_EXTRA_CONFIG`
 # One of the current use cases for this is enabling custom TinyMCE plugins
+# (TINYMCE_ADDITIONAL_PLUGINS) and overriding the TinyMCE configuration
+# (TINYMCE_CONFIG_OVERRIDES).
 JS_ENV_EXTRA_CONFIG = {}
 
 ############################### PIPELINE #######################################
diff --git a/xmodule/js/src/html/edit.js b/xmodule/js/src/html/edit.js
index bb92d8c848d9..88863d8e2a03 100644
--- a/xmodule/js/src/html/edit.js
+++ b/xmodule/js/src/html/edit.js
@@ -208,6 +208,12 @@
               }
             });
           }
+
+          // apply configuration overrides if have been defined
+          var tinyMceConfigOverrides = process.env.JS_ENV_EXTRA_CONFIG.TINYMCE_CONFIG_OVERRIDES;
+          if (tinyMceConfigOverrides) {
+            Object.assign(tinyMceConfig, tinyMceConfigOverrides);
+          }
         }
 
         this.tiny_mce_textarea = $(".tiny-mce", this.element).tinymce(tinyMceConfig);