diff --git a/layout/style/test/test_non_content_accessible_env_vars.html b/layout/style/test/test_non_content_accessible_env_vars.html
index d9714216b78a..6faa32e96437 100644
--- a/layout/style/test/test_non_content_accessible_env_vars.html
+++ b/layout/style/test/test_non_content_accessible_env_vars.html
@@ -6,6 +6,7 @@
 <script>
 const NON_CONTENT_ACCESSIBLE_ENV_VARS = [
   "-moz-gtk-csd-titlebar-radius",
+  "-moz-gtk-csd-tooltip-radius",
   "-moz-gtk-csd-minimize-button-position",
   "-moz-gtk-csd-maximize-button-position",
   "-moz-gtk-csd-close-button-position",
diff --git a/servo/components/style/custom_properties.rs b/servo/components/style/custom_properties.rs
index a9c2173a21c4..b948299444ac 100644
--- a/servo/components/style/custom_properties.rs
+++ b/servo/components/style/custom_properties.rs
@@ -142,7 +142,7 @@ macro_rules! lnf_int_variable {
     }};
 }
 
-static CHROME_ENVIRONMENT_VARIABLES: [EnvironmentVariable; 9] = [
+static CHROME_ENVIRONMENT_VARIABLES: [EnvironmentVariable; 10] = [
     lnf_int_variable!(
         atom!("-moz-mac-titlebar-height"),
         MacTitlebarHeight,
@@ -158,6 +158,11 @@ static CHROME_ENVIRONMENT_VARIABLES: [EnvironmentVariable; 9] = [
         TitlebarRadius,
         int_pixels
     ),
+    lnf_int_variable!(
+        atom!("-moz-gtk-csd-tooltip-radius"),
+        TooltipRadius,
+        int_pixels
+    ),
     lnf_int_variable!(
         atom!("-moz-gtk-csd-close-button-position"),
         GTKCSDCloseButtonPosition,
diff --git a/toolkit/content/xul.css b/toolkit/content/xul.css
index bd80261aee27..191748cd53b0 100644
--- a/toolkit/content/xul.css
+++ b/toolkit/content/xul.css
@@ -369,48 +369,34 @@ tooltip {
   max-width: 40em;
   overflow: clip;
   pointer-events: none;
-}
 
-/**
- * It's important that these styles are in a UA sheet, because the default
- * tooltip is native anonymous content
- */
-@media (-moz-platform: linux) {
-  tooltip {
+  /**
+   * It's important that these styles are in a UA sheet, because the default
+   * tooltip is native anonymous content
+   */
+  @media (-moz-platform: linux) {
     padding: 6px 10px; /* Matches Adwaita. */
     line-height: 1.4;  /* For Noto Sans; note that 1.2 may clip descenders. */
+    border: .5px solid color-mix(in srgb, currentColor 60%, transparent);
+    @media (-moz-gtk-csd-transparency-available) {
+      border-radius: env(-moz-gtk-csd-tooltip-radius);
+    }
   }
-}
-
-@media (-moz-platform: macos) {
-  tooltip {
+  @media (-moz-platform: macos) {
     padding: 2px 6px; /* Matches native metrics. */
   }
-}
-
-@media (-moz-platform: windows) {
-  tooltip {
+  @media (-moz-platform: windows) {
     appearance: none;
     border: 1px solid;
-  }
 
-  /* TODO(emilio): Probably make InfoText/InfoBackground do the right thing and
-   * remove this? */
-  @media not (prefers-contrast) {
-    tooltip {
-      background-color: #f9f9fb;
-      color: black;
-      border-color: #67676c;
+    /* TODO(emilio): Probably make InfoText/InfoBackground do the right thing and
+     * remove this? */
+    @media not (prefers-contrast) {
+      background-color: light-dark(#f9f9fb, #2b2a33);
+      color: light-dark(black, white);
+      border-color: light-dark(#67676c, #f9f9fb);
       border-radius: 4px;
     }
-
-    @media (prefers-color-scheme: dark) {
-      tooltip {
-        background-color: #2b2a33;
-        color: white;
-        border-color: #f9f9fb;
-      }
-    }
   }
 }
 
diff --git a/widget/LookAndFeel.h b/widget/LookAndFeel.h
index ed0bfd9ab140..36e2b7ac7b92 100644
--- a/widget/LookAndFeel.h
+++ b/widget/LookAndFeel.h
@@ -305,6 +305,9 @@ class LookAndFeel {
     /** GTK button-to-button spacing in the inline axis */
     TitlebarButtonSpacing,
 
+    /** GTK tooltip radius */
+    TooltipRadius,
+
     /**
      * Corresponding to dynamic-range.
      * https://drafts.csswg.org/mediaqueries-5/#dynamic-range
diff --git a/widget/gtk/gtk3drawing.cpp b/widget/gtk/gtk3drawing.cpp
index cfe6c187fea9..c0b3fe185d4b 100644
--- a/widget/gtk/gtk3drawing.cpp
+++ b/widget/gtk/gtk3drawing.cpp
@@ -56,20 +56,6 @@ static gint moz_gtk_get_tab_thickness(GtkStyleContext* style);
 
 static void Inset(GdkRectangle*, const GtkBorder&);
 
-static void InsetByMargin(GdkRectangle*, GtkStyleContext* style);
-
-static void moz_gtk_add_style_margin(GtkStyleContext* style, gint* left,
-                                     gint* top, gint* right, gint* bottom) {
-  GtkBorder margin;
-
-  gtk_style_context_get_margin(style, gtk_style_context_get_state(style),
-                               &margin);
-  *left += margin.left;
-  *right += margin.right;
-  *top += margin.top;
-  *bottom += margin.bottom;
-}
-
 static void moz_gtk_add_style_border(GtkStyleContext* style, gint* left,
                                      gint* top, gint* right, gint* bottom) {
   GtkBorder border;
@@ -96,14 +82,6 @@ static void moz_gtk_add_style_padding(GtkStyleContext* style, gint* left,
   *bottom += padding.bottom;
 }
 
-static void moz_gtk_add_margin_border_padding(GtkStyleContext* style,
-                                              gint* left, gint* top,
-                                              gint* right, gint* bottom) {
-  moz_gtk_add_style_margin(style, left, top, right, bottom);
-  moz_gtk_add_style_border(style, left, top, right, bottom);
-  moz_gtk_add_style_padding(style, left, top, right, bottom);
-}
-
 static void moz_gtk_add_border_padding(GtkStyleContext* style, gint* left,
                                        gint* top, gint* right, gint* bottom) {
   moz_gtk_add_style_border(style, left, top, right, bottom);
@@ -598,14 +576,6 @@ static void Inset(GdkRectangle* rect, const GtkBorder& aBorder) {
   rect->height -= aBorder.top + aBorder.bottom;
 }
 
-// Inset a rectangle by the margins specified in a style context.
-static void InsetByMargin(GdkRectangle* rect, GtkStyleContext* style) {
-  GtkBorder margin;
-  gtk_style_context_get_margin(style, gtk_style_context_get_state(style),
-                               &margin);
-  Inset(rect, margin);
-}
-
 // Inset a rectangle by the border and padding specified in a style context.
 static void InsetByBorderPadding(GdkRectangle* rect, GtkStyleContext* style) {
   GtkStateFlags state = gtk_style_context_get_state(style);
@@ -617,20 +587,6 @@ static void InsetByBorderPadding(GdkRectangle* rect, GtkStyleContext* style) {
   Inset(rect, border);
 }
 
-static void moz_gtk_draw_styled_frame(GtkStyleContext* style, cairo_t* cr,
-                                      const GdkRectangle* aRect,
-                                      bool drawFocus) {
-  GdkRectangle rect = *aRect;
-
-  InsetByMargin(&rect, style);
-
-  gtk_render_background(style, cr, rect.x, rect.y, rect.width, rect.height);
-  gtk_render_frame(style, cr, rect.x, rect.y, rect.width, rect.height);
-  if (drawFocus) {
-    gtk_render_focus(style, cr, rect.x, rect.y, rect.width, rect.height);
-  }
-}
-
 /* See gtk_range_draw() for reference.
  */
 static gint moz_gtk_scale_paint(cairo_t* cr, GdkRectangle* rect,
@@ -916,54 +872,6 @@ static gint moz_gtk_arrow_paint(cairo_t* cr, GdkRectangle* rect,
   return MOZ_GTK_SUCCESS;
 }
 
-static gint moz_gtk_tooltip_paint(cairo_t* cr, const GdkRectangle* aRect,
-                                  GtkWidgetState* state,
-                                  GtkTextDirection direction) {
-  // Tooltip widget is made in GTK3 as following tree:
-  // Tooltip window
-  //   Horizontal Box
-  //     Icon (not supported by Firefox)
-  //     Label
-  // Each element can be fully styled by CSS of GTK theme.
-  // We have to draw all elements with appropriate offset and right dimensions.
-
-  // Tooltip drawing
-  GtkStyleContext* style =
-      GetStyleContext(MOZ_GTK_TOOLTIP, state->image_scale, direction);
-  GdkRectangle rect = *aRect;
-  gtk_render_background(style, cr, rect.x, rect.y, rect.width, rect.height);
-  gtk_render_frame(style, cr, rect.x, rect.y, rect.width, rect.height);
-
-  // Horizontal Box drawing
-  //
-  // The box element has hard-coded 6px margin-* GtkWidget properties, which
-  // are added between the window dimensions and the CSS margin box of the
-  // horizontal box.  The frame of the tooltip window is drawn in the
-  // 6px margin.
-  // For drawing Horizontal Box we have to inset drawing area by that 6px
-  // plus its CSS margin.
-  GtkStyleContext* boxStyle =
-      GetStyleContext(MOZ_GTK_TOOLTIP_BOX, state->image_scale, direction);
-
-  rect.x += 6;
-  rect.y += 6;
-  rect.width -= 12;
-  rect.height -= 12;
-
-  InsetByMargin(&rect, boxStyle);
-  gtk_render_background(boxStyle, cr, rect.x, rect.y, rect.width, rect.height);
-  gtk_render_frame(boxStyle, cr, rect.x, rect.y, rect.width, rect.height);
-
-  // Label drawing
-  InsetByBorderPadding(&rect, boxStyle);
-
-  GtkStyleContext* labelStyle =
-      GetStyleContext(MOZ_GTK_TOOLTIP_BOX_LABEL, state->image_scale, direction);
-  moz_gtk_draw_styled_frame(labelStyle, cr, &rect, false);
-
-  return MOZ_GTK_SUCCESS;
-}
-
 static gint moz_gtk_resizer_paint(cairo_t* cr, GdkRectangle* rect,
                                   GtkWidgetState* state,
                                   GtkTextDirection direction) {
@@ -1409,23 +1317,6 @@ gint moz_gtk_get_widget_border(WidgetNodeType widget, gint* left, gint* top,
     case MOZ_GTK_FRAME:
       w = GetWidget(MOZ_GTK_FRAME);
       break;
-    case MOZ_GTK_TOOLTIP: {
-      // In GTK 3 there are 6 pixels of additional margin around the box.
-      // See details there:
-      // https://github.com/GNOME/gtk/blob/5ea69a136bd7e4970b3a800390e20314665aaed2/gtk/ui/gtktooltipwindow.ui#L11
-      *left = *right = *top = *bottom = 6;
-
-      // We also need to add margin/padding/borders from Tooltip content.
-      // Tooltip contains horizontal box, where icon and label is put.
-      // We ignore icon as long as we don't have support for it.
-      GtkStyleContext* boxStyle = GetStyleContext(MOZ_GTK_TOOLTIP_BOX);
-      moz_gtk_add_margin_border_padding(boxStyle, left, top, right, bottom);
-
-      GtkStyleContext* labelStyle = GetStyleContext(MOZ_GTK_TOOLTIP_BOX_LABEL);
-      moz_gtk_add_margin_border_padding(labelStyle, left, top, right, bottom);
-
-      return MOZ_GTK_SUCCESS;
-    }
     /* These widgets have no borders, since they are not containers. */
     case MOZ_GTK_SPLITTER_HORIZONTAL:
     case MOZ_GTK_SPLITTER_VERTICAL:
@@ -1670,8 +1561,6 @@ gint moz_gtk_widget_paint(WidgetNodeType widget, cairo_t* cr,
       return moz_gtk_text_view_paint(cr, rect, state, direction);
     case MOZ_GTK_DROPDOWN:
       return moz_gtk_combo_box_paint(cr, rect, state, direction);
-    case MOZ_GTK_TOOLTIP:
-      return moz_gtk_tooltip_paint(cr, rect, state, direction);
     case MOZ_GTK_FRAME:
       return moz_gtk_frame_paint(cr, rect, state, direction);
     case MOZ_GTK_RESIZER:
diff --git a/widget/gtk/nsLookAndFeel.cpp b/widget/gtk/nsLookAndFeel.cpp
index 9fce9aae65a3..cde08e07241f 100644
--- a/widget/gtk/nsLookAndFeel.cpp
+++ b/widget/gtk/nsLookAndFeel.cpp
@@ -1176,6 +1176,11 @@ nsresult nsLookAndFeel::NativeGetInt(IntID aID, int32_t& aResult) {
       // No GTK API for checking if inverted colors is enabled
       aResult = 0;
       break;
+    case IntID::TooltipRadius: {
+      EnsureInit();
+      aResult = EffectiveTheme().mTooltipRadius;
+      break;
+    }
     case IntID::TitlebarRadius: {
       EnsureInit();
       aResult = EffectiveTheme().mTitlebarRadius;
@@ -2100,6 +2105,7 @@ void nsLookAndFeel::PerThemeData::Init() {
   mInfo.mFg = GetTextColor(style);
   style = GetStyleContext(MOZ_GTK_TOOLTIP);
   mInfo.mBg = GetBackgroundColor(style, mInfo.mFg);
+  mTooltipRadius = GetBorderRadius(style);
 
   style = GetStyleContext(MOZ_GTK_MENUITEM);
   {
diff --git a/widget/gtk/nsLookAndFeel.h b/widget/gtk/nsLookAndFeel.h
index d92812844846..5387c87a9c44 100644
--- a/widget/gtk/nsLookAndFeel.h
+++ b/widget/gtk/nsLookAndFeel.h
@@ -167,6 +167,7 @@ class nsLookAndFeel final : public nsXPLookAndFeel {
 
     float mCaretRatio = 0.0f;
     int32_t mTitlebarRadius = 0;
+    int32_t mTooltipRadius = 0;
     int32_t mTitlebarButtonSpacing = 0;
     char16_t mInvisibleCharacter = 0;
     bool mMenuSupportsDrag = false;
diff --git a/widget/gtk/nsNativeThemeGTK.cpp b/widget/gtk/nsNativeThemeGTK.cpp
index 08e2966d02be..c354843da68f 100644
--- a/widget/gtk/nsNativeThemeGTK.cpp
+++ b/widget/gtk/nsNativeThemeGTK.cpp
@@ -291,9 +291,6 @@ bool nsNativeThemeGTK::GetGtkWidgetAndState(StyleAppearance aAppearance,
           *aWidgetFlags = GTK_ARROW_LEFT;
       }
       break;
-    case StyleAppearance::Tooltip:
-      aGtkWidgetType = MOZ_GTK_TOOLTIP;
-      break;
     case StyleAppearance::ProgressBar:
       aGtkWidgetType = MOZ_GTK_PROGRESSBAR;
       break;
@@ -868,7 +865,6 @@ bool nsNativeThemeGTK::GetWidgetPadding(nsDeviceContext* aContext,
   }
   switch (aAppearance) {
     case StyleAppearance::Toolbarbutton:
-    case StyleAppearance::Tooltip:
     case StyleAppearance::MozWindowButtonClose:
     case StyleAppearance::MozWindowButtonMinimize:
     case StyleAppearance::MozWindowButtonMaximize:
@@ -919,21 +915,6 @@ auto nsNativeThemeGTK::IsWidgetNonNative(nsIFrame* aFrame,
     return NonNative::No;
   }
 
-  // As an special-case, for tooltips, we check if the tooltip color is the
-  // same between the light and dark themes. If so we can get away with drawing
-  // the native widget, see bug 1817396.
-  if (aAppearance == StyleAppearance::Tooltip) {
-    auto darkColor =
-        LookAndFeel::Color(StyleSystemColor::Infotext, ColorScheme::Dark,
-                           LookAndFeel::UseStandins::No);
-    auto lightColor =
-        LookAndFeel::Color(StyleSystemColor::Infotext, ColorScheme::Light,
-                           LookAndFeel::UseStandins::No);
-    if (darkColor == lightColor) {
-      return NonNative::No;
-    }
-  }
-
   // If the non-native theme doesn't support the widget then oh well...
   if (!Theme::ThemeSupportsWidget(aFrame->PresContext(), aFrame, aAppearance)) {
     return NonNative::No;
@@ -1068,7 +1049,6 @@ bool nsNativeThemeGTK::WidgetAttributeChangeRequiresRepaint(
   // Some widget types just never change state.
   if (aAppearance == StyleAppearance::Progresschunk ||
       aAppearance == StyleAppearance::ProgressBar ||
-      aAppearance == StyleAppearance::Tooltip ||
       aAppearance == StyleAppearance::MozWindowDecorations) {
     return false;
   }
@@ -1117,7 +1097,6 @@ nsNativeThemeGTK::ThemeSupportsWidget(nsPresContext* aPresContext,
     case StyleAppearance::Tab:
     // case StyleAppearance::Tabpanel:
     case StyleAppearance::Tabpanels:
-    case StyleAppearance::Tooltip:
     case StyleAppearance::NumberInput:
     case StyleAppearance::PasswordInput:
     case StyleAppearance::Textfield:
@@ -1178,14 +1157,7 @@ nsITheme::Transparency nsNativeThemeGTK::GetWidgetTransparency(
     return Theme::GetWidgetTransparency(aFrame, aAppearance);
   }
 
-  switch (aAppearance) {
-    // Tooltips use gtk_paint_flat_box() on Gtk2
-    // but are shaped on Gtk3
-    case StyleAppearance::Tooltip:
-      return eTransparent;
-    default:
-      return eUnknownTransparency;
-  }
+  return eUnknownTransparency;
 }
 
 already_AddRefed<Theme> do_CreateNativeThemeDoNotUseDirectly() {
diff --git a/widget/nsXPLookAndFeel.cpp b/widget/nsXPLookAndFeel.cpp
index d9116c8e83d8..7ed9d7d4a068 100644
--- a/widget/nsXPLookAndFeel.cpp
+++ b/widget/nsXPLookAndFeel.cpp
@@ -158,6 +158,7 @@ static const char sIntPrefs[][45] = {
     "ui.touchDeviceSupportPresent",
     "ui.titlebarRadius",
     "ui.titlebarButtonSpacing",
+    "ui.tooltipRadius",
     "ui.dynamicRange",
     "ui.panelAnimations",
     "ui.hideCursorWhileTyping",
diff --git a/xpcom/ds/StaticAtoms.py b/xpcom/ds/StaticAtoms.py
index 6cf910227b5c..564ba8ff271e 100644
--- a/xpcom/ds/StaticAtoms.py
+++ b/xpcom/ds/StaticAtoms.py
@@ -2293,6 +2293,7 @@ STATIC_ATOMS = [
     Atom("_moz_gtk_csd_available", "-moz-gtk-csd-available"),
     Atom("_moz_gtk_csd_transparency_available", "-moz-gtk-csd-transparency-available"),
     Atom("_moz_gtk_csd_titlebar_radius", "-moz-gtk-csd-titlebar-radius"),
+    Atom("_moz_gtk_csd_tooltip_radius", "-moz-gtk-csd-tooltip-radius"),
     Atom("_moz_gtk_csd_titlebar_button_spacing", "-moz-gtk-csd-titlebar-button-spacing"),
     Atom("_moz_gtk_csd_minimize_button", "-moz-gtk-csd-minimize-button"),
     Atom("_moz_gtk_csd_minimize_button_position", "-moz-gtk-csd-minimize-button-position"),