diff --git a/content/treestyletab/treestyletab.css b/content/treestyletab/treestyletab.css
index 2196a72b..ed04eb82 100644
--- a/content/treestyletab/treestyletab.css
+++ b/content/treestyletab/treestyletab.css
@@ -467,34 +467,28 @@ toolbar.treestyletab-tabbar-toolbar-ready:not([nowindowdrag="true"]),
 
 .tabbrowser-tabs[treestyletab-animation-enabled="true"][treestyletab-mode="vertical"]
   .tabbrowser-tab:not([treestyletab-collapsed-done="true"]) {
-	-moz-transition: var(--tst-tab-animation-vertical);
 	transition: var(--tst-tab-animation-vertical);
 }
 .tabbrowser-tabs[movingtab][treestyletab-animation-enabled="true"][treestyletab-mode="vertical"]
   .tabbrowser-tab:not([treestyletab-collapsed-done="true"]) {
-	-moz-transition: var(--tst-tab-animation-vertical);
 	transition: var(--tst-tab-animation-vertical);
 }
 
 .tabbrowser-tabs[treestyletab-animation-enabled="true"]:not([treestyletab-mode="vertical"]):not([treestyletab-tab-inverted="true"])
   .tabbrowser-tab:not([treestyletab-collapsed-done="true"]) {
-	-moz-transition: var(--tst-tab-animation-top);
 	transition: var(--tst-tab-animation-top);
 }
 .tabbrowser-tabs[movingtab][treestyletab-animation-enabled="true"]:not([treestyletab-mode="vertical"]):not([treestyletab-tab-inverted="true"])
   .tabbrowser-tab:not([treestyletab-collapsed-done="true"]) {
-	-moz-transition: var(--tst-tab-animation-top);
 	transition: var(--tst-tab-animation-top);
 }
 
 .tabbrowser-tabs[treestyletab-animation-enabled="true"]:not([treestyletab-mode="vertical"])[treestyletab-tab-inverted="true"]
   .tabbrowser-tab:not([treestyletab-collapsed-done="true"]) {
-	-moz-transition: var(--tst-tab-animation-bottom);
 	transition: var(--tst-tab-animation-bottom);
 }
 .tabbrowser-tabs[movingtab][treestyletab-animation-enabled="true"]:not([treestyletab-mode="vertical"])[treestyletab-tab-inverted="true"]
   .tabbrowser-tab:not([treestyletab-collapsed-done="true"]) {
-	-moz-transition: var(--tst-tab-animation-bottom);
 	transition: var(--tst-tab-animation-bottom);
 }
 
@@ -600,10 +594,6 @@ window[chromehidden~="toolbar"]
 /* full tooltip */
 
 #treestyletab-full-tree-tooltip[popup-shown="true"] {
-	-moz-transition: margin-left 0.2s ease-out,
-	                 margin-top 0.2s ease-out,
-	                 max-height 0.2s ease-out,
-	                 max-width 0.2s ease-out;
 	transition: margin-left 0.2s ease-out,
 	            margin-top 0.2s ease-out,
 	            max-height 0.2s ease-out,
@@ -615,7 +605,6 @@ window[chromehidden~="toolbar"]
 }
 
 #treestyletab-full-tree-tooltip[popup-shown="true"] > arrowscrollbox {
-	-moz-transition: opacity 0.2s ease-out;
 	transition: opacity 0.2s ease-out;
 	opacity: 1;
 }
diff --git a/modules/browser.js b/modules/browser.js
index 112e9f21..daa4bab1 100644
--- a/modules/browser.js
+++ b/modules/browser.js
@@ -666,9 +666,9 @@ TreeStyleTabBrowser.prototype = inherit(TreeStyleTabWindow.prototype, {
 			let style = item.style;
 			style.MozMarginStart = '';
 
-			let transitionStyleBackup = style.transition || style.MozTransition || '';
+			let transitionStyleBackup = style.transition || '';
 			if (aJustNow)
-				style.MozTransition = style.transition = 'none';
+				style.transition = 'none';
 
 			let className = item.className.replace(removeFaviconizedClassPattern, '');
 			if (faviconized)
@@ -690,7 +690,7 @@ TreeStyleTabBrowser.prototype = inherit(TreeStyleTabWindow.prototype, {
 				// "transition" must be cleared after the reflow.
 				this.timers[key] = setTimeout((function() {
 					try {
-						style.MozTransition = style.transition = transitionStyleBackup;
+						style.transition = transitionStyleBackup;
 					}
 					catch(e) {
 						this.defaultErrorHandler(e);
@@ -6001,7 +6001,7 @@ TreeStyleTabBrowser.prototype = inherit(TreeStyleTabWindow.prototype, {
 		}
 
 		var self = this;
-		var CSSTransitionEnabled = ('transition' in aTab.style || 'MozTransition' in aTab.style);
+		var CSSTransitionEnabled = ('transition' in aTab.style);
 		if (CSSTransitionEnabled) {
 			aTab.__treestyletab__updateTabIndentTask = function(aTime, aBeginning, aChange, aDuration) {
 				delete aTab.__treestyletab__updateTabIndentTask;
@@ -6648,7 +6648,7 @@ TreeStyleTabBrowser.prototype = inherit(TreeStyleTabWindow.prototype, {
 
 		aTab.setAttribute(this.kCOLLAPSING_PHASE, aCollapsed ? this.kCOLLAPSING_PHASE_TO_BE_COLLAPSED : this.kCOLLAPSING_PHASE_TO_BE_EXPANDED );
 
-		var CSSTransitionEnabled = ('transition' in aTab.style || 'MozTransition' in aTab.style);
+		var CSSTransitionEnabled = ('transition' in aTab.style);
 
 		var maxMargin;
 		var offsetAttr;
diff --git a/skin/classic/treestyletab/square/tab-surface.css b/skin/classic/treestyletab/square/tab-surface.css
index db185a92..fe538ce1 100644
--- a/skin/classic/treestyletab/square/tab-surface.css
+++ b/skin/classic/treestyletab/square/tab-surface.css
@@ -5,7 +5,6 @@
 .tabbrowser-tabs:not([treestyletab-tabbar-position="top"])
   .tabbrowser-tab
   .tab-background {
-	-moz-transition: background 0.5s ease-out !important;
 	transition: background 0.5s ease-out !important;
 }