diff --git a/firefox/css/main.css b/firefox/css/main.css
index 7d97676..33901aa 100644
--- a/firefox/css/main.css
+++ b/firefox/css/main.css
@@ -9,6 +9,8 @@ html[global_enable="true"][remove_home_link="true"] a:not(#logo)[href="/"],
 html[global_enable="true"][remove_explore_link="true"] a[href="/feed/trending"],
 html[global_enable="true"][remove_explore_link="true"] a[href="/feed/explore"],
 
+html[global_enable="true"][remove_thumbnail_mouseover_effect="true"] #mouseover-overlay,
+
 html[global_enable="true"][remove_play_next_button="true"] a.ytp-next-button,
 
 html[global_enable="true"][remove_comments="true"] #comments,
diff --git a/firefox/css/options.css b/firefox/css/options.css
index 160a092..b35aa82 100644
--- a/firefox/css/options.css
+++ b/firefox/css/options.css
@@ -8,6 +8,7 @@ html[remove_info_cards="true"] .remove_info_cards .inactive,
 html[remove_home_link="true"] .remove_home_link .inactive,
 html[remove_logo_link="true"] .remove_logo_link .inactive,
 html[remove_explore_link="true"] .remove_explore_link .inactive,
+html[remove_thumbnail_mouseover_effect="true"] .remove_thumbnail_mouseover_effect .inactive,
 html[remove_play_next_button="true"] .remove_play_next_button .inactive,
 html[remove_comments="true"] .remove_comments .inactive,
 html[remove_chat="true"] .remove_chat .inactive,
@@ -28,6 +29,7 @@ html[remove_info_cards="false"] .remove_info_cards .active,
 html[remove_home_link="false"] .remove_home_link .active,
 html[remove_logo_link="false"] .remove_logo_link .active,
 html[remove_explore_link="false"] .remove_explore_link .active,
+html[remove_thumbnail_mouseover_effect="false"] .remove_thumbnail_mouseover_effect .active,
 html[remove_play_next_button="false"] .remove_play_next_button .active,
 html[remove_comments="false"] .remove_comments .active,
 html[remove_chat="false"] .remove_chat .active,
diff --git a/firefox/js/content-script.js b/firefox/js/content-script.js
index 6d427d5..732e73d 100644
--- a/firefox/js/content-script.js
+++ b/firefox/js/content-script.js
@@ -6,20 +6,21 @@ if (typeof browser === 'undefined') {
 // Some global constants.
 const HTML = document.documentElement;
 const SETTINGS_LIST = {
-  "global_enable":            { defaultValue: true,  eventType: 'click'  },
-  "remove_homepage":          { defaultValue: true,  eventType: 'change' },
-  "remove_sidebar":           { defaultValue: true,  eventType: 'change' },
-  "remove_end_of_video":      { defaultValue: true,  eventType: 'change' },
-  "remove_info_cards":        { defaultValue: false, eventType: 'change' },
-  "remove_home_link":         { defaultValue: false, eventType: 'change' },
-  "remove_logo_link":         { defaultValue: false, eventType: 'change' },
-  "remove_explore_link":      { defaultValue: false, eventType: 'change' },
-  "remove_play_next_button":  { defaultValue: false, eventType: 'change' },
-  "remove_comments":          { defaultValue: false, eventType: 'change' },
-  "remove_chat":              { defaultValue: false, eventType: 'change' },
-  "redirect_off":             { defaultValue: true,  eventType: 'change' },
-  "redirect_to_subs":         { defaultValue: false, eventType: 'change' },
-  "redirect_to_wl":           { defaultValue: false, eventType: 'change' },
+  "global_enable":                     { defaultValue: true,  eventType: 'click'  },
+  "remove_homepage":                   { defaultValue: true,  eventType: 'change' },
+  "remove_sidebar":                    { defaultValue: true,  eventType: 'change' },
+  "remove_end_of_video":               { defaultValue: true,  eventType: 'change' },
+  "remove_info_cards":                 { defaultValue: false, eventType: 'change' },
+  "remove_home_link":                  { defaultValue: false, eventType: 'change' },
+  "remove_logo_link":                  { defaultValue: false, eventType: 'change' },
+  "remove_explore_link":               { defaultValue: false, eventType: 'change' },
+  "remove_thumbnail_mouseover_effect": { defaultValue: false, eventType: 'change' },
+  "remove_play_next_button":           { defaultValue: false, eventType: 'change' },
+  "remove_comments":                   { defaultValue: false, eventType: 'change' },
+  "remove_chat":                       { defaultValue: false, eventType: 'change' },
+  "redirect_off":                      { defaultValue: true,  eventType: 'change' },
+  "redirect_to_subs":                  { defaultValue: false, eventType: 'change' },
+  "redirect_to_wl":                    { defaultValue: false, eventType: 'change' },
 };
 
 // Initialize HTML attributes with local settings, or default.
diff --git a/firefox/js/options.js b/firefox/js/options.js
index c17d897..7629d4e 100644
--- a/firefox/js/options.js
+++ b/firefox/js/options.js
@@ -6,20 +6,21 @@ if (typeof browser === 'undefined') {
 // Some global constants.
 const HTML = document.documentElement;
 const SETTINGS_LIST = {
-  "global_enable":           { defaultValue: true,  eventType: 'click' },
-  "remove_homepage":         { defaultValue: true,  eventType: 'click' },
-  "remove_sidebar":          { defaultValue: true,  eventType: 'click' },
-  "remove_end_of_video":     { defaultValue: true,  eventType: 'click' },
-  "remove_info_cards":       { defaultValue: false, eventType: 'click' },
-  "remove_home_link":        { defaultValue: false, eventType: 'click' },
-  "remove_logo_link":        { defaultValue: false, eventType: 'click' },
-  "remove_explore_link":     { defaultValue: false, eventType: 'click' },
-  "remove_play_next_button": { defaultValue: false, eventType: 'click' },
-  "remove_comments":         { defaultValue: false, eventType: 'click' },
-  "remove_chat":             { defaultValue: false, eventType: 'click' },
-  "redirect_off":            { defaultValue: true,  eventType: 'click' },
-  "redirect_to_subs":        { defaultValue: false, eventType: 'click' },
-  "redirect_to_wl":          { defaultValue: false, eventType: 'click' },
+  "global_enable":                     { defaultValue: true,  eventType: 'click' },
+  "remove_homepage":                   { defaultValue: true,  eventType: 'click' },
+  "remove_sidebar":                    { defaultValue: true,  eventType: 'click' },
+  "remove_end_of_video":               { defaultValue: true,  eventType: 'click' },
+  "remove_info_cards":                 { defaultValue: false, eventType: 'click' },
+  "remove_home_link":                  { defaultValue: false, eventType: 'click' },
+  "remove_logo_link":                  { defaultValue: false, eventType: 'click' },
+  "remove_explore_link":               { defaultValue: false, eventType: 'click' },
+  "remove_thumbnail_mouseover_effect": { defaultValue: false, eventType: 'click' },
+  "remove_play_next_button":           { defaultValue: false, eventType: 'click' },
+  "remove_comments":                   { defaultValue: false, eventType: 'click' },
+  "remove_chat":                       { defaultValue: false, eventType: 'click' },
+  "redirect_off":                      { defaultValue: true,  eventType: 'click' },
+  "redirect_to_subs":                  { defaultValue: false, eventType: 'click' },
+  "redirect_to_wl":                    { defaultValue: false, eventType: 'click' },
 };
 const VALID_SETTINGS = Object.keys(SETTINGS_LIST);
 
diff --git a/firefox/options.html b/firefox/options.html
index 479ec10..453ef8e 100644
--- a/firefox/options.html
+++ b/firefox/options.html
@@ -58,6 +58,10 @@
       <fieldset>
         <legend>More removal options</legend>
 
+        <div class="remove_thumbnail_mouseover_effect">
+          <div class="option_name_container"><a class="active">🚫</a><a class="inactive">🟢</a> Thumbnail mouseover effect</div>
+        </div>
+
         <div class="remove_play_next_button">
           <div class="option_name_container"><a class="active">🚫</a><a class="inactive">🟢</a> Play next button</div>
         </div>